Sunday, November 20, 2011

Poisoned Places: Part 2 - Smack dab in the middle of it!

Here is what NPR has to say about their Special Series NPR News Investigates called: "Poisoned Places: Toxic Air, Neglected Communities."
Two decades ago, Democrats and Republicans together sought to protect Americans from nearly 200 dangerous chemicals in the air they breathe. That goal remains unfulfilled. Today, hundreds of communities are still exposed to the pollutants, which can cause cancer, birth defects and other serious health issues. A secret government 'watch list' underscores how much government knows about the threat – and how little it has done to address it.
In my last post, I wrote about one of these "poisoned" places, Hayden, Arizona, Titled "EPA Takes Action Against Toxic Arizona Copper Plant."

According to NPR there is a "secret government 'watch list' underscores how much government knows about the threat – and how little it has done to address it."  So what is this secret government 'watch list' NPR speaks of?
The Bush administration's EPA faced criticism for not being tough enough on chronic polluters, so in 2004 it created a confidential watch list to manage the problem.
According to EPA reports, when regulators don't crack down within nine months of learning that a facility is a chronic or serious violator of the rules, the facility automatically pops onto the watch list. As a result, the agency says, some facilities may end up on the list in error.
Some of the facilities on the list likely are the "worst of the worst" polluters, but others may be breaking the rules in ways that do not pose significant risks for human health or the environment, says Grant Nakayama, who headed the EPA's enforcements under President Bush.
Apparently, Hayden, Arizona is on that secret list.  Is it a "worst of the worst" polluter or is it on there for  "breaking the rules in ways that do not pose significant risks for human health or the environment?"

That's an important distinction for two reasons.  One, you imply poisoning when you call someone a polluter, this leads to fear, concern, and stress for those who live in that "place."  Two, we have limited resources to spend, lets take that money and protect human health and the environment from real danger, not perceived risk.  Soapbox /off

Let's also look at the question: "how little it has done to address it."

“The bottom line is that the whole town is contaminated,” said Betty Amparano, who was born in Hayden and has lived here most of her life.  Which led the Center for Public Integrity to write:
In some families, generations claim to have suffered ill effects from bad air. Deaths from cancer are common. Regulators have done little; for people who live here, the sense of betrayal is profound.
Is there any way possible to look at this objectively?  I mean you have a town that is located for the most part within a factory that smelts copper ore.  What possible conclusion can one come up with other than the people in Hayden, Arizona have been "poisoned" and there has been "little done to address it."

Let's look at the evidence the NPR and the Center for Public Integrity put forth to support the claim of a "threat" and a "sense of betrayal."

1. We have a copper smelter
2. The town is right next to the copper smelter
3. We have citizens claiming they "suffered ill effects from bad air."
4. The Center for Public Integrity states "deaths from cancer are common."
5. "A copper smelter failed to keep toxic air pollution in check."
6. "The state failed to lean on the smelter’s owner, Asarco."
7. "The federal government failed, until days ago, to override the state."
8. A "finding of violation" claims the company has been continuously emitting illegal amounts of lead, arsenic and eight other dangerous compounds for six years.
9. The EPA says its monitors detected lead at two to three times federal limits on some days during 2011.
10. The EPA ordered Asarco to remove and replace the soil from more than 200 yards in Hayden after finding soil contaminated with lead and arsenic.
11. Does the smelter have a "License to Pollute" as the Center for Public Integrity claims in their video on the NPR web page?

Let's get 1 and 2 out of the way.  Yes, there is a copper smelter and the town is right next to it.  When you look at the EPA map and the satellite photo, it looks like a bad place to live.  The copper smelter in Hayden, Arizona has all the bells and whistles needed to make such a "poisoned places" claim.  I mean, look at this map from the EPA that they handed out to the community:

Handouts from EPA’s Open House and Community Meeting, January 9, 10, 2008

Maybe a satellite image might work a bit better:

Google Maps
Do you see what I see?  They built a smelter right smack in the middle of the town of Hayden Arizona!  That's similar to putting the Alamo smack dab in the middle of San Antonio, Texas!

Alamo in San Antonio, Texas

You can understand why Hayden citizen Betty Amparano sees it as failures "that all but ruined this wisp of a town occurred on multiple levels."

But here is one of the facts in play.  Hayden and Winkelman are there because of the copper smelter.

According to the EPA:

EPA Region 9 HHRA Report - Full
This is one of the fundamental problems we have in looking at the risk of an operation, such as a smelter or refinery, in an objective manner.  What is the risk now, not what was the risk pre-1990 Clean Air Act or the contamination that resulted before we had the environmental laws we now have in place.

The fact of the matter is this:  50 years before we had an EPA we had a copper smelter in the town of Hayden, Arizona.  For 50 years - till present day laws and regulation - that copper smelter did what it was designed to do - smelt copper - which results in ore being refined, tailings being produced, heat being generated, and emissions put into the air.

"I remember clouds of blue smoke coming down into the playgrounds in the community and coughing and your eyes burning," recalls Manny Armenta, 56, who represents union workers at Asarco.

And I remember the air being so bad in Garden Grove, California that it burned my eyes when we went outside to play. That was Orange County back in the 60s before it was all grown up. That was then, this is now.

So one again, we have two opposing claims:
A "finding of violation" claims the company has been continuously emitting illegal amounts of lead, arsenic and eight other dangerous compounds for six years.
 "Our smelter is in compliance with its air permit," writes Tom Aldrich, an Asarco spokesman. "Asarco works closely with its regulators and proactively seeks innovations as science evolves and environmental laws and rules are updated."

Two men claim they're Jesus one of them must be wrong.

Next post: Poisoned Places: Part 3 - The whole towns contaminated.


Friday, November 18, 2011

Poisoned Places: Part 1 - That claim makes it sound real bad

If you have done anything today, it involved something that was produced.  Everything we do depends on something being produced - made.

This is a given, and it needs to be understood and accepted.  If you fly on an airplane, it's not just the fuel that was burned to move you from point A to point B, but the fuel burned by all those who support the flight.  Not only is fuel burned, but the materials that went into the airplane and airport had to be produced.

Case in point, the radar we use to get us from A to B safely requires electricity.  Electricity must be produced and it must be transported from that generation point to the radar.  That transmission is done through copper lines, and that copper must be produced.

Which brings me to this post.  A given:  If we are going to use copper it must be mined from the ground and smelted to produce a usable product.  If you don't want to mine or smelt then you will not produce copper or any of the other materials we use and depend on day to day.

That's a given.  There is no way around mining and smelting to produce copper.

The question now must focus on this: Can we mine and smelt copper in a way that is protective of public health and the environment?

Well of course we can, right?  I mean we put a bunch of guys on the moon, we can mine and smelt copper safely.  The question now becomes: Are we mining and smelting copper in a way to protect public health and the environment?

One group says they are, another says they are not.  Or, as Dire Straits says in their 1982 song "Industrial Disease" (no irony intended with that title): Two men say they're Jesus one of them must be wrong.

NPR - who I listen to and support - has an ongoing series called "Poisoned Places" and this Thursday's episode was on a copper smelter in Hayden, Arizona that "has drawn complaints about toxic pollution for years."

If you have read any of my other posts you will come to see I spend very little time on waste and a whole bunch on looking at exposure and the risk to health from that exposure.  So when someone uses the term "poison" to describe a place, I'm skeptical as why they chose that particular word.

Here is how the word "poison" is defined by Merriam-Webster:
a : a substance that through its chemical action usually kills, injures, or impairs an organism
b : something destructive or harmful
For me, the NPR title implies that the people of the town of Hayden, Arizona are being killed, injured, or impaired by a copper smelter that is putting into their environment something that is destructive or harmful.

Is that what is happening now?  Is that what has been happening over the last couple of years?  Let's face facts here.  Prior to about 1980, what industry put into the air, water, and soil was not good for public health and the environment.  Since 1980, industry has changed as laws on what can be put into the air, water, and land have forced compliance with thresholds, controls, and monitoring designed to be protective of public health and the environment.

Did this smelter in Hayden, Arizona at one time (its been in operation since 1912) cause harm to public health and the environment?  I would hazard a guess as to yeah, it most likely did.  Is the smelter still causing harm to public health and the environment?  That's the $64,000 question.

NPR, through the Center for Public Integrity makes a number of statements indicating that there is still harm to the public, hence showing up in NPRs Poisoned Places series.  After all, if it wasn't poisoning anyone, why would they be reporting on it?

Here's the thing.  If you are going to make a claim that something is bad, dangerous, unhealthy, or a poison, you need to have data to support that.  And, if you have data, you need to understand what the data tells you and how it fits in with the claim of risk or harm.

Let's look at how Center for Public Integrity starts of their webpage article:
“The bottom line is that the whole town is contaminated,” said [Betty] Amparano, who was born in Hayden and has lived here most of her life.
Soil tainted by airborne metals has been excavated from hundreds of yards. In some families, generations claim to have suffered ill effects from bad air. Deaths from cancer are common. Regulators have done little; for people who live here, the sense of betrayal is profound.
Should we believe this?  Is the "whole town" contaminated?  Are deaths from cancer "common?"  Have regulators "done little?"

First, lets look at the claim: "In some families, generations claim to have suffered ill effects from bad air. Deaths from cancer are common."

Where is the data?  Sounds cruel, doesn't it?  But that's how it has to be.  For the Center for Public Integrity to report that claim, they should have looked into information to support that claim.  Was their an epidemiological study done?  What do the medical professionals have to say?  Did Arizona's Public Health officials look into this?

Two men claim they're Jesus one of them must be wrong.

According to the American Cancer Society, the lifetime probability of developing cancer for men, 2005-2007 was a risk of 1 in 2 (slide 17).  Do all of these men live near a copper smelter?  Is the incidence of cancer in men higher or lower than this in Hayden, Arizona?

But now that NPR and the Center for Public Integrity has your attention, it seems only probable that they can build a case to support such a claim.

But what they will build is nothing more sound than a straw house.  The truth is a wolf, and you know what he can do to a straw house.

Next post: Poisoned Places: Part 2 - Smack dab in the middle of it!


Tuesday, November 15, 2011

Playing the part of Dale Gribble...Chuck Norris!

Whoa! Hold on, son! I want you to keep an open mind so you can make an informed decision! If you want, you can read a bloated government report on smoking, or go straight to the horse's mouth and get the facts from the tobacco industry.  Dale Gribble


According to Chuck Norris in his Nov 4, 2011 C-Force article:
Many attribute the increase in the rate of ASDs to children's being exposed to significant quantities of thimerosal, a mercury-based compound that has been used since the 1930s as a preservative in certain vaccines and pharmaceutical products to prevent bacterial and fungal contamination.
What Chuck bases this on is information he obtained from two websites, The National Autism Association (NAA) and the Coalition for Mercury-free Drugs (CoMeD).  That's as far as his "research" apparently went on this topic.

Chuck, like many others in this camp, seem to be convinced that the spike in Autism cases we saw in the 1990s was the result of the preservative - thimerosal - a mercury-based compound.  Here is what Chuck has to say about thimerosal:
Since 2001 in the U.S., no new vaccine licensed by the Food and Drug Administration for use in children has contained thimerosal, except for ones to prevent influenza. Nevertheless, the CDC [Centers for Disease Control] continues to recommend some routine vaccines with "trace amounts of thimerosal" for children younger than 6.
A reasonably intelligent person might be wondering why Chuck would find it necessary to tell his reader who posed the question...:
Chuck, I keep hearing conflicting reports that certain vaccines are dangerous and even can cause autism in children. What do you know? – Cheryl M., Charlotte, N.C.
 ...about a material that is no longer used.

Here is what the CDC states, according to Chuck:
According to the CDC's website, however, "to date, the studies continue to show that vaccines are not associated with ASDs. ... The most recent and rigorous scientific research does not support the argument that thimerosal-containing vaccines are harmful. ... Is thimerosal in vaccines safe? Yes."
So if thimerosal is no longer used and if it is used it is "safe," why is Chuck bringing this issue back up?  You will have to ask him on that, all I can do is speculate as to his reasoning.

What I can reasonably speculate on is this:  Chuck and his anti-vaccine cohorts do not trust the CDC.  Not only that, they don't trust "the nation's bastion of authoritative health advice" - the Institute of Medicine.

They don't trust them, but they do trust those who agree with them.  Guys like Dr. Boyd Haley - the one who the NAA attributes the claim that "recent studies have confirmed the association between the use of thimerosal and autism has moved from "biologically plausible" to a "biological certainty." (see previous post)

Let's look at what Chuck says in his C-Force article.
Nevertheless, the CDC [Centers for Disease Control] continues to recommend some routine vaccines with "trace amounts of thimerosal" for children younger than 6.
Here is what the FDA - the agency with authority over vaccines - says about thimerosal:
Thimerosal has been removed from or reduced to trace amounts in all vaccines routinely recommended for children 6 years of age and younger, with the exception of inactivated influenza vaccine (see Table 1). A preservative-free version of the inactivated influenza vaccine (contains trace amounts of thimerosal) is available in limited supply at this time for use in infants, children and pregnant women. Some vaccines such as Td, which is indicated for older children (≥ 7 years of age) and adults, are also now available in formulations that are free of thimerosal or contain only trace amounts. Vaccines with trace amounts of thimerosal contain 1 microgram or less of mercury per dose.
If you are interested in this topic, you should spend time looking at Table 1.  Of the 30 different manufactured vaccines on the list, only 5 contain trace amounts of thimerosal, four of those are for Seasonal Trivalent Influenza (for which three manufactures do not use thimerosal) and one is for Tetanus "which is indicated for older children (≥ 7 years of age) and adults."

Had Chuck done his own research he would have been able to accurately report this which would have allowed him to correctly inform his reader that one; vaccines are safe, and two; she and other concerned parents can request thimerosal-free vaccines.

My question is why Chuck, the NAA, and CoMeD continue to present vaccines as a likely culprit for autism?  Since January 2003 thimerosal has been out of the vaccines we routinely give children.

There is little current data that I could easily find showing the trend of autism over time.  What I did find looks at California and is based on how California schools must report.



If you look at these graphs you will see an increase in Autism since 2002.  The California data is based on "The disability categories and enrollment breakdown in California for individuals (newborn through twenty-two years of age)."  One would assume that as time progressed from 2002, more and more children entering into California Schools would have received vaccines without thimerosal.  Even factoring in new autism cases in 7 & 8 year olds - who may have received thimerosal - the number of children vaccinated without it would far exceed this group.  Even accounting for a lag in time from thimerosal vaccination to diagnosis, there would be a dip in the number of cases around 2007 as five year olds entered the school system who were vaccinated after 2002.

No matter how you look at it, these two graphs show an increase in the number of autism cases after thimerosal was removed.  Interesting...  So how come Chuck and his fellow anti-vaccine folks still want to tie thimerosal to autism?

You will notice I used two different data sources (albeit they most likely used the same data) to show an increase in autism since 2002.  You see, Chuck and company believe that a

Here is what Chuck wrote:
The deliberate avoidance and falsification of medical data to support CDC bias is heinous enough, but the fact that such information is manipulated to practice medicine on our nation's children is monstrous malpractice and even premeditated malevolence.  I agree wholeheartedly with Lisa Sykes, president of CoMeD, who summarized the CDC cover-up: "This type of malfeasance should not be tolerated by those who are entrusted with our children's health and well-being."
Cover-up?  Wow, that's a pretty strong accusation to make.  I bet Chuck must have some real powerful evidence to show this.  He must have come across a smoking gun that would unequivocally show that the CDC "ignored certain data and misled the medical community and public by insinuating that thimerosal in vaccines does not increase the risk of autism."

Exhibit A "Chuck's smoking gun"
...the Coalition for Mercury-free Drugs exposed a federal cover-up between the CDC and vaccine researchers. Despite the fact that the CDC received an email from CoMeD in 2002 that revealed a causal relationship between the removal of thimerosal from vaccines and a decline in the rate of autism, the CDC encouraged the publication of a study in Pediatrics...
Almost inconceivably, the study in Pediatrics actually purported that autism rates increased after thimerosal was removed. coauthor, from Aarhus University, Denmark, was aware of the omission and alerted CDC officials in a 2002 email, stating, 'Attached I send you the short and long manuscript about Thimerosal and autism in Denmark ... I need to tell you that the figures do not include the latest data from 2001 ... but the incidence and prevalence are still decreasing in 2001.'
Exhibit B "The Actual Pediatrics Publication"

Thimerosal and the Occurrence of Autism: Negative Ecological Evidence From Danish Population-Based Data (1)  Note: This publication is copyrighted and may not be available online.  According to this paper:
The incidence of autism remained fairly constant during the period of use of thimerosal in Denmark, and the rise in incidence beginning in 1991 continued even in the group of children born after the discontinuation of thimerosal.
This was shown with the following graph:

 Notice that vertical line at year 1992?  Here is what the authors conclude:
The discontinuation of thimerosal-containing vaccines in Denmark in 1992 was followed by an increase in the incidence of autism. Our ecological data do not support a correlation between thimerosal-containing vaccines and the incidence of autism. 
Denmark removed thimerosal from its vaccines in 1992, 10 years before the United States.  Notice how the graph shows an increase in autism for all age groups.  If thimerosal was the culprit, there would be a downward trend.  There wasn't one seen in Denmark and there isn't one seen in the United States after 2002.

Notice, however, that there is a dip in the 5-6 and 7-9 age groups.  That dip takes place a full 7 years after the thimerosal was removed.

Cue music....

Enter Exhibit C "The Email"

Chuck went to CoMeD's website and found this:
Documents obtained via the Freedom of Information Act (FOIA) show that CDC officials were aware of Danish data indicating a connection between removing Thimerosal (49.55% mercury) and a decline in autism rates.  Despite this knowledge, these officials allowed a 2003 article to be published in Pediatrics that excluded this information, misrepresented the decline as an increase, and led to the mistaken conclusion that Thimerosal in vaccines does not cause autism.
And what is this "knowledge" that the CDC officials were aware of:
One coauthor, from Aarhus University, Denmark, was aware of the omission and alerted CDC officials in a  2002 email, stating "Attached I send you the short and long manuscript about Thimerosal and autism in Denmark … I need to tell you that the figures do not include the latest data from 2001 … but the incidence and prevalence are still decreasing in 2001"
You can read the email on CoMeD's website.   Why is this an issue for CoMeD and Chuck?
Nevertheless, in the final draft version of the publication submitted to Pediatrics, the data from 2001 showing a decline in autism was not mentioned.  Ignoring this omission, the CDC continued to endorse the article and, in a December 10, 2002  recommendation letter to the editor of Pediatrics, encouraged expedited review and publication of the article. The misleading Danish article was published by Pediatrics in 2003.
I am unsure if any of the the CoMed folks or Chuck bothered to ask the email writer or the authors why that 2001 information was not relevant to the conclusion.  It's an interesting bit of data because it begs the question as to what may be causing that decline in 2001.  It also begs the question why there is a decline in Denmark but not in California.  What it does not do is give any additional information to the paper's conclusion:
The discontinuation of thimerosal-containing vaccines in Denmark in 1992 was followed by an increase in the incidence of autism.
A decline in 2001, even one starting in 1999, would have nothing whatsoever to do with the removal of thimerosal.  That decline is nine years after removal, so diagnosis of children with Autism would have taken place during that time frame and there would be no connection to thimerosal in children born after 1992.  If thimerosal was the culprit, there would be a decrease as less children developed autism.  That's not what the graph shows, and including this smoking gun email data does not change that.


Yeah, I know.  In 1994 they changed the way autism is diagnosed.

The increase in the incidence of autism from 1990 on may be attributable to more attention being drawn to the syndrome of autism and to a change in the diagnostic criteria from the ICD-8 to the ICD-10 in 1994.

So if more children were diagnosed with autism because of this change, you would still see a decrease over time (5 years) as less children developed autism if thimerosal was a factor.  In addition, the data from California shows Autism on the rise after it was removed from united States vaccines.

So what's behind all this?  Possibly nothing more than an increase in attention as the author's state.  That's not universally shared, however:
A study by researchers at the UC Davis M.I.N.D. Institute has found that the seven- to eight-fold increase in the number children born in California with autism since 1990 cannot be explained by either changes in how the condition is diagnosed or counted — and the trend shows no sign of abating.
So what's the cause of this increase?  Here is what the UC Davis M.I.N.D. folks think:

Published in the January 2009 issue of the journal Epidemiology, results from the study also suggest that research should shift from genetics to the host of chemicals and infectious microbes in the environment that are likely at the root of changes in the neurodevelopment of California’s children.
“It’s time to start looking for the environmental culprits responsible for the remarkable increase in the rate of autism in California,” said UC Davis M.I.N.D. Institute researcher Irva Hertz-Picciotto, a professor of environmental and occupational health and epidemiology and an internationally respected autism researcher.
One "environmental culprit" we can stop looking at?  Thimerosal and vaccines.

As Dale Gribble might say.
Vaccines don't kill people, Chuck Norris does!

A less scientific- but informative - blog on this topic can be found here


Sunday, November 13, 2011

Six degrees of irresponsibility from Chuck Norris

Our Wednesday edition of The Eagle newspaper ran a syndicated piece of nonsense by Chuck Norris.

Chuck - who I would not take acting lessons from. let alone listen to him about public health issues - was asked by a reader:
Chuck, I keep hearing conflicting reports that certain vaccines are dangerous and even can cause autism in children. What do you know? – Cheryl M., Charlotte, N.C.
Chuck's response in his commentary called "C-Force" was titled:
Link between autism, vaccines 'biological certainty'
What Chuck doesn't understand is that "biological certainty" is only one of the nine Hill's Criteria of Causation "minimal conditions needed to establish a causal relationship between two items." (1) (2)

But what do you expect from a guy who's research into this topic was gleaned from two anti-vaccine websites. In fact, if you read what ol' Chuck writes, and then read what's on these two websites (3) (4), you would swear it was plagiarism, but that's for another post I suppose.

If you have read any of my previous blogs, you know that the anti-vaccine rhetoric really gets to me.  It's not good science supporting it, it's dangerous to children who go un-immunized, and it creates unnecessary concern and stress for parents who want to do what is best for their children.

Chuck Norris should know better than to print something as fact that is not thoroughly researched.  His editors should have fact checked his writing, and my newspaper should have done so as well.

There is no credible evidence linking vaccines to autism.  Yes, both these two websites Chuck regurgitated "fact" from claim to have evidence showing a "CDC cover-up" and "biological certainty" are easily explained and do nothing to advance the thimerosal-autism correlation other than make a general connection that both can be present.

I'll write more on the "cover-up" in a later post, for now, I want to show you how six degrees of irresponsibility from Chuck Norris works:
1. Chuck Norris writes an article titled: Link between autism, vaccines 'biological certainty'
2. The "biological certainty" claim comes from the National Autism Association website (3) which states:"Recent studies have confirmed the association between the use of thimerosal and autism has moved from "biologically plausible" to a "biological certainty" and attributes this to a scientist named "Boyd Haley."
3. Boyd Haley is a co-author on a paper titled:   "Mercury and autism: Accelerating Evidence?" in Activitas Nervosa Superior; Jul 2007; 49, 1/2; ProQuest Central pg. 22.  In this paper the authors state:
Source: Mercury and autism: Accelerating Evidence?
4. This paper is critical of the paper "Thimerosal and the Occurrence of Autism: Negative Ecological Evidence From Danish Population-Based Data" in Pediatrics 2003;112;604.  This is the paper that the other website claims there was a "CDC cover-up."
The plot now thickens....

Doing a Texas A&M Library search for journal articles attributed to Dr. Boyd Haley, I find nothing written by him stating or using the term "biological certainty."  I did a Google search using the words:  "biological certainty Boyd Haley"  Nothing pops up except page after page quoting the National Autism Association's claim that Dr. Haley made this claim.

So I do a Google search using the words "Boyd Haley"

....which brings up the 5th degree of irresponsibility from Chuck Norris:
5. Clicking on the third link I read this: "OSR was developed and patented by Dr. Boyd Haley PhD, who has said that his OSR product will permanently bind with Mercury 1 million times better than either DMSA, DMPS, or EDTA."(5)
According to this website:
"Boyd Haley is highly respected and well known throughout the community of holistic Mercury-free dentists and "Defeat Autism Now!" (DAN!) medical doctors. Boyd Haley is a vigorous opponent of the use of Mercury in vaccines and dental fillings, and he is very active in the Defeat Autism Now (DAN!) community. DAN! is a nationwide association of medical doctors who believe that Autism can be treated primarily with Mercury chelation, anti-Candida medications, and diet. The DAN doctors are in the process now of transitioning away from DMSA, towards OSR, as their Mercury chelator of choice. 
Which brings me to the 6th degree of irresponsibility
6. According to the first website on the search page , the Chicago Tribune reports the following:
The problem with folks like Chuck Norris and the National Autism Association and The Coalition for Mercury-free Drugs (CoMeD) is that they want so badly to find a cause that they are willing to latch on to anyone that supports their thinking.  Even snake oil salesmen.

Chuck Norris wrote this irresponsible piece of nonsense without spending anytime asking the question, are these statements valid?  Why would the National Autism Association still use anything attributed to Boyd Haley?  Why would website after website regurgitate the same National Autism Association claim of "biological certainty" without looking up to see who and what the guy is involved with?

Good science demands objectivity.

If you don't want thimerosal in your kid's vaccination ask your Doctor to provide thimerosal free vaccines and boosters (yeah, I know its no longer used....I'm trying to get folks past this reason not to vaccinate).

And Chuck, stick to writing about exercise and a good diet.  Leave science to those who are willing to do the research.

For a recent scientific journal article on the topic of Thimerosal and Autism click here.

Edit.  Notes


Wednesday, November 9, 2011

A five mile radius kill zone that never happened

Saw this Letter to the Editor in the Dallas Morning News last week:


What caught my eye was the statement "killed every living thing within a five-mile radius."

Just that afternoon in my DOT Hazmat Employee class I was teaching in Mesquite we were discussing "poison inhalation hazard materials and how the Emergency Response Guidebook's (ERG) Table of Initial Isolation looks at the hazard of the poison based on its toxicity and how that relates to DOT's use of the "hazard zone A, B, C, and D."

You will notice that the compound "hydrogen sulfide" has a downwind night time protection distance of 3.9 miles.  In other words, the ERG considers a large release of hydrogen sulfide to not present a health hazard to the public 3.9 miles from the source.

Ellen Childress, the letter writer, claims:
A blowout of a pipeline carrying natural gas from wells to plant in Van Zandt County some years ago killed every living thing within a five-mile radius.
What, I thought to myself, would have been transported in a pipeline that could kill "every living thing within a five-mile radius."

Ms. Childress believes that the culprit was hydrogen sulfide:
Not a word was said in the article about the extreme danger of transporting hydrogen sulfide gas, a component of the "natural" gas when it comes out of the ground, through neighborhoods to a processing plant.
Understanding the concept of dose, dispersion, and the concentration of hydrogen gas sent in pipelines, I was curious as to what happened in " Van Zandt County some years ago."  Was there a blowout that killed "every living thing within a five-mile radius?"

Why would Ms Childress make this claim if it were not true?  And, more importantly, if it wasn't true, it was now in the newspaper for all to see and believe it to be true.  How does one make an informed decision on risk if the risk is under or over inflated?

It was easy for me to discount the "five mile radius" claim as impossible.  It was therefore easy for me to believe that whatever happened in Van Zandt County did not kill every living thing in that area.

So what, if anything, did happen "some years ago?"

In Texas the Railroad Commission (RRC) is in charge of oil & gas drilling and production.  The one thing the Railroad Commission does not have jurisdiction over is railroads - but that's for another blog post I suppose.

The Texas RRC logs "Blowouts and Well Control Problems" and posts them on their web site.  So I searched for blowouts in Van Zandt County and this RRC website for Region 5 came up.

Based on this data, there was a fire in 1972 and a hydrogen sulfide (H2S) release in 1978.  The RRC does not report any deaths or injuries for any of the five reported issues in Van Zandt County.

I did a search for a newspaper account of the release.  Here is what I found:


Searching for "Van Zandt County" and "hydrogen" provided no other hits.

So, what's the lesson here?  Don't put anything in print that has not been confirmed.  Why five miles?  Why not 10 or three?

So when she asks: "What kind of protections do homeowners and others have today against that kind of disaster?"

"That kind of disaster" never happened.

There are real risks and real protections.  Focus on those in order to make your decision.


Sunday, November 6, 2011

Laundered Shop Towels: 15 - Why I spend the effort

Caveat emptor: "Let the buyer beware."

I could leave it at that and make this a very short post.

Here is what drives me to spend my free time researching and writing about the misuse of science by those scientists and professionals to which we have an implied trust that their conclusions and findings are unbiased and sound.
Kimberly-Clark wants to sell more disposable wipes.  They used a PE, two public health PhDs (one an ex-EPA director), and "an environmental and risk science consulting firm renowned for their expertise in Toxicology, epidemiology, Risk Assessment, Product Safety, Contaminant Fate and Transport, and Environmental/Forensic Chemistry." to imply a risk when using a competitor's product to increase sales. (1)
Dr. Andrew Wakefield "a medial researcher who published his work in the Lancet stood to gain financially from his purported findings because of his involvement in a lawsuit against manufacturers of the MMR vaccine." (2)
Chiropractors, who hold doctorate degrees, bill our insurance providers for services using "cold laser" and "applied kinesiology."
Alisa Rich, who holds a Masters in Public Health and is now a PhD that has been hired to teach risk as an Adjunct Professor at UNT, insists that her air sampling "confirmed the presence in high concentrations of carcinogenic and neurotoxin compounds in ambient air near and/or on residential properties" in the town of Dish, Texas. (3)
Caveat emptor?

No, I choose to write about their findings and methods in an attempt to educate and explain why their premise is false.  It's easy to call someone wrong and leave it at that. I choose to support it, because at the end of the day these professionals - who by their education, association, and credentials - infer our trust, make money and further an agenda at someone else's expense.

And what is that expenses?  Not just money lost due to fear, but the added stress that results from that fear.  How many children remain un-vaccination for preventable childhood diseases because of fear of Autism?

How many Dish residents worry about neurological problems and cancer?  How many folks living in the town of Dish Texas are fearful of the gas wells in their city?  They are fearful based on what a group of highly credentialed and learned scientists have put out in front of them as their potential risk?

"And what does these posts on shop towels have to do with hazardous waste?" one might be wondering?  Well in a roundabout way, understanding how we assign a health risk to an item or activity all works towards protecting public health and the environment.

It is a difficult enough job balancing the need to make a profit with the EHS goal of protecting employee and public health as well as the environment.  A worker believing that his employer may be harming him by forcing him to use a contaminated laundered shop towel, now sets in motion the need to prove there is no harm.  I am pretty sure that's exactly what Kimberly-Clark was aiming for based on their brochure.  How does the EHS department prove there is no risk when this Gradient report - written by a former EPA administrator and PhD - claims there is?

So, fine...take the easy way out and stop using laundered shop towels.  Problem solved.  Except Kimberly-Clark forgets to tell its customers that when you use a disposable shop towel, that towel will be discarded making it a solid waste which will then require a hazardous waste determination to be made.  That's not an issue when you use a laundered shop towel.

Here is what the EPA has to say about laundered shop towels:
Reusable wipes are part of a more systematic handling system. In general, a laundry owns reusable industrial wipes, rents them to generators, and collects them for laundering on a regular basis. Generators receive deliveries of wipes from the laundries, use them, and accumulate used wipes. Drivers, most often employed by the laundries, pick up the contaminated industrial wipes, replacing them with clean wipes at the same time, and then return the soiled wipes to the laundry. Once at the laundry, the wipes are then counted to assure the laundry is getting back from the generator the same number sent out and, finally, are cleaned before entering the cycle again.
This lead the EPA...
In the early 1990s, EPA developed a policy that deferred determinations and interpretations regarding regulation of solvent-contaminated industrial wipes to states authorized to implement the federal hazardous waste program or to the EPA region in the cases where a state is not authorized.
...and because of this policy a bit of confusion:
This policy led to the application of different regulatory schemes for both types of industrial wipes in EPA regions and states. Although the states differ in the details of their policies, in general, they regulate disposable industrial wipes as a hazardous waste when they are contaminated with a solvent that is listed or exhibits a hazardous waste characteristic. On the other hand, many, but not all, states provide regulatory relief for reusable contaminated wipes sent to an industrial laundry or other facility for cleaning and reuse. In about half the cases, this regulatory relief is in the form of an exclusion from the definition of hazardous waste, whereas other states provide an exclusion from the definition of solid waste.
The substantive difference between these two approaches is that materials excluded from the definition of solid waste are not considered a waste at all, and are not subject to Federal RCRA regulation, whereas materials excluded from the definition of hazardous waste are considered to be wastes that, when certain conditions are met, do not need to be managed as hazardous wastes.  
For reusable industrial wipes, the conditions for the various exclusions vary from state to state, but most require that the containers of wipes not contain free liquids, and require that the laundry discharge to a Publicly Owned Treatment Works (POTW) or be permitted under the Clean Water Act. Some states have established other requirements such as requiring generators to manage contaminated wipes according to the hazardous waste accumulation standards prior to laundering, and requiring generators to file a one-time notice under the land disposal restriction (LDR) program
Laundered shop towels are considered reusable.  Reusable shop towels that are laundered and the wash water sent to a POTW or discharged under a NPDES permit are NOT hazardous waste.  Using Kimberly-Clark disposable shop towels WILL be solid waste and MAY meet the defintion of a hazardous waste.

You can see the problem Kimberly-Clark faces here.  How do they counter the reality that each and every one of their disposable shop towels will require a hazardous waste determination where as none of that is required if you use a reusable shop towel, especially one that is laundered.

It's all about the words "reusable" and "disposable."  And Kimberly-Clark's plan to counter that?  Convince workers that laundered shop towels contain "Concentrations of metals in laundered shop wipes can result in exposures (as evaluated using the methodology presented in this report) which exceed toxicity criteria for certain metals." (4) and then ask them "Why take the risk?" (5)

So this brings up an interesting question for Kimberly-Clark.  If laundered shop towels exceed toxicity criteria, what would be the toxicity criteria for a disposable shop towel that has not been cleaned with soap and water and dried under heat?


Interesting question, especially when you read this little bit of information from that same EPA proposed rule found in the Federal Resister (Vol. 68, No. 224 / Thursday, November 20, 2003).
Specifically, in 1985, EPA received a petition, pursuant to 40 CFR.260.20, from the Kimberly-Clark Corporation, a manufacturer of disposable industrial wipes, that asked EPA to exclude disposable wipes from the definition of hazardous waste. The petition stated that these materials are over-regulated because the amount of solvent in the wipes is insignificant and because the disposable wipes do not pose a threat to human health and the environment even when disposed of in a municipal solid waste landfill. In 1987, EPA received a second rulemaking petition from the Scott Paper Company that reiterated many of Kimberly-Clark’s points and added that the hazardous waste regulations are not necessary because contaminated disposable wipes are handled responsibly, make up just 1% of a generator’s waste stream, and could be beneficial to the operation of incinerators because of their heat value.
Kimberly-Clark has been dealing with this issue of hazardous waste determination for their product for a long time.  Allowing laundered shop towels to be managed outside of RCRA presents a disadvantage to Kimberly-Clark.  Guess what?  I agree with Kimberly-Clark!  I think that the great majority of all shop towels if properly managed, laundered, reused, burned for energy, or disposed in a Solid Waste landfill -  do not pose a threat to human health and the environment.

The wheels of regulatory change, however, move much too slow to have this issued resolved correctly.  Since 1985, 2003, and then in 2010 it remains unresolved. Still, Kimberly-Clark, you cannot have it both ways.

Spent shop towels are either a risk to human health and the environment or they are not.  Don't even think about telling me there is a difference between putting it to the face and putting it in a landfill.  TCLP anyone!

So I spend my time researching and writing this blog to help me understand the manipulated world around me.  I am not so foolish to believe my blog will change anything.  Misinformation is exactly what they want and use, and they have the power and structure to keep it up.  I mean, look how many people buy those silly latex "holographic" bracelets for balance? (see Power Balance)

Still, the internet does provide room for all different types of voices, even mine.  It's there for anyone to see and use.  It's the best I can do to counter bad science, even if it is read by so few and buried within the noise produced by search engine algorithms somewhere on page 9 or 10.

If it clears the air for one person and helps them make a sound decision to stop or move forward, then it's time well spent.


Monday, October 10, 2011

Laundered Shop Towels: 14 - Should you believe them?

In my first post on this topic I asked:
Should we accept it based on the reputation of Gradient and the credentials of the three authors?  Or should we look deeper into the study to see how they came up with data that affords Kimberly-Clark the ability to ask workers: Why risk it?  Who's counting on you?
I then went on to say:
Well I have looked into it.  I can support my conclusion that there is no additional risk to a worker using a laundered shop towel.  Period.  Should you believe me?  No, not until you read what I am putting forth as my reasons why this study is flawed and their conclusion false.
So here we are after 13 posts on this topic.  I have presented how Gradient came to conclude that there is a risk

Kimberly-Clark sure wants to take Gradient's findings at face value.  What business wouldn't want to show how bad the other option is by claiming:
"Two studies conducted during the last 8 years show that laundered shop towels contain toxic heavy metals even after laundering." (1)
And they get to do that with unabashed glee simply because of a study prepared interdependently by:
"an environmental and risk science consulting firm renowned for their expertise in Toxicology, epidemiology, Risk Assessment, Product Safety, Contaminant Fate and Transport, and Environmental/Forensic Chemistry." (1)
But those ratios Gradient reports in Table 8a have a much different meaning when you look at how they were generated as well as what the comparison is made to:

Let's look at each one of my issues with their model, calculation, and assumptions.  If there is an increase in risk high enough to warrant discontinuing the use of laundered shop towels, it must be supported by the science presented in Gradient's reports.

Gradient claims that the average concentration of lead (the metal with the highest exceedance ratios -Table 8a) in laundered shop towels is 100 mg/kg.  If that average is not correct, then none of the intake values they calculated are correct.

Based on the minimum and maximum concentrations they present in Table 4 of their study, and the standard deviation reported, it is evident that the average Loads they use are skewed to represent a higher concentration of metals than would naturally be found.

The calculated mean - or average - is supposed to represent the true mean of the population.  Based on the high variability in the concentrations they report (as shown by the standard deviation exceeding the mean) it is highly unlikely that the averages they used to determine the Load represent what is actually found on a laundered shop towel.  It is, in most likelihood, magnitudes higher than what would normally be found.

Let's look at an example to illustrate this:

Here are 25 values representing the lowest concentration detected (1.7) and the highest (600) for lead.  All the other numbers are just numbers I came up with.  The numbers in blue represent all the values less than the mean, the numbers in red represent concentrations higher than the mean.  Using these numbers I was able to get close to the mean and standard deviation reported by Gradient.

Since 100 mg/kg is the number Gradient uses to estimate the lead Load on the laundered shop towel, if these were the actual values detected, 22 towels encountered would have a concentration of lead on them less than 100 and three would be above.

In a normal distribution, "100" would be the average encountered. so at the end of the day, after handling 12 shop towels, the load encountered would be around 100.  That's based on a normal distribution, where 100 is in the middle, half lower and half higher.  In my example 92% of the towels encountered have a lead concentration lower than 100.  See previous post on this topic.

I don't know what the actual concentrations for lead are, but I do know that the average of 100 is not a true representation of what is normally found on laundered shop towels.  It is too high based on the standard deviation reported.  This means that the Load for the towel they calculated is too high as well.

Even if the mean concentrations Gradient reports were correct, there is still the issue on whether or not the metals can be dislodged from the towel and onto the hand.  That's the whole purpose of calculating a Load, to see what is available to enter the mouth from the hand.  I discussed that issue in this post, and it is extremely relevant in determining the validity of their intake values.

The fact that an object may contain a high concentration of metals does not warrant concern if those metals can not be transported into the receptor, in this case from the hand into the worker's mouth.  In order for Gradient's model to hold true, metals must come off the towel and onto the hand - Tt/h.  Why Gradient did not look at what, if any, metals could dislodge from the towels is beyond me.  Even Adam and Jamie of the Mythbusters could have figured out a sound way to determine this.  And they're not PhDs!

So I'll call the "Load" and "Tt/h" part of Gradient's calculation:

But let's look at Load from a different angle.  Gradient claims that the intake of lead a worker might encounter on laundered shop towels is "11" times higher than the CalEPA NSRL for lead.  That is, the lead Load is significant enough to bring about 10 additional cancers for every 100,000 workers using laundered shop towels. (We would expect one cancer at the NSRL).  See previous post.

As I showed in that post, 100,000 workers would use 11.8 billion laundered shop towels.  Are you willing to contend that the 25 shop towels Gradient tested represent the Load on 11.8 billion towels?

Not only are the Load values Gradient used in question, but the intake they calculated requires the worker to place their hand to their mouth each time a laundered shop towel is used.  For these exceedance values to be true, a worker must bring their hand (single) to their mouth 117,600 times (12 towels, 245 day, 40 years).  And each time they bring their hand to their mouth, 13% of what is on the hand comes off the hand and is consumed.

Where did Gradient come up with that number of 13%? That number is half the amount of soil a child consumes if all of the soil consumed came from the hands.  Read my post on this for more information on how Gradient derived this.

Why Gradient chose to use a child's hand and not an adults when calculating this transfer efficiency can only be answered by them.  Had they used an adult's hand, the HTE would have been 6%.  But that's still based on a faulty premise that all of the soil consumed by the adult came solely from the hands.

A better - or more sound - method would have been to use CalEPA's hand to mouth calculation (see post). Once again, why Gradient made up their own method for deriving an HTE can only be answered by them.  It does seem odd though, that they would use CalEPA's MADL and NSRL thresholds and not their methodology.  Peculiar.

Based on this, I'll call the "HTE" part of Gradient's calculation "Busted" as well:

And what about Kimberly-Clark's claim:
"Just how far did they exceed these limits? Here’s one example: the study found that a worker using a typical number of shop towels per day can be exposed to up to 3,600 times the health-based exposure limit set for lead." (4th page)
What does that mean, "3600 times?"  That health based exposure limit is the CalEPA MADL for lead, and had Kimberly-Clark been more forthcoming, they would have let the worker know that the value CalEPA uses is based on health of the fetus and is set 1000 times lower than the no observable health effects level described in the literature.  See this post and this post.

What Gradient should have done was calculate potential exposure risk using EPA's method for determining the clean up level of lead in soil, which is also based on the health of he fetus (post).  EPA's "preliminary remediation goals (PRG) are based on the amount of lead intake from soil that would bring about a level of lead in the blood harmful to the fetus. At that blood level concentration of lead, Gradient's intake value exceeds the EPA 'safe" level by 3 times.  Using the more appropriate 6% HTE (based on an adult hand), the exceedance ratio is 1.3 - using all the other assumptions and values used by Gradient.  3600 times higher refers to a value used to determine when signage and notification is not required by a business.

So I'll call Kimberly-Clark's claim in their brochure:

There you have it.  I've shown you theirs...and I've shown you mine.

Should you believe Kimberly-Clark when they state:
Heavy metals have been found in laundered shop towels in amounts that exceed health-based exposure guidelines related to cancer and non-cancer related health issues, like reproductive and developmental effects.
Should we still conclude that laundered shop towels pose a risk to workers?

You have read my posts and can easily check my sources and work my calculations.  Here is what I think, based on what my research into this matter has shown me:

Which leads me to only one conclusion - Gradient's study and conclusion is....

Next post: Laundered Shop Towels: 15 - Why I spend the effort


Saturday, October 8, 2011

Laundered Shop Towels: 13 - 100,000 workers using 12 laundered shop towels per day

If 100,000 workers using 12 laundered shop towels for 245 days per year for 40 years consumed 15 ug of lead each and every time the 12 towels were handled, we would expect to see one additional cancer as a result of that exposure.

If 100,000 worker using 12 laundered shop towels for 245 days per year for 40 years consumed 168 ug of lead each and every time the 12 towels were handled, we would expect to see how many additional cancers as a result of that exposure?

In my last post, I showed the formula CalEPA uses to calculate the NSRL - No Significant Risk Level - value of 15 ug/day of lead.  Here is how the CalEPA calculates that risk of one in 100,000 for the NSRL:

Source  Page 15

Doing a bit of algebra - I think that's what it's called - we switch the variables around so we can solve for "R"-  which is the cancer risk.
  • R = (0.168 mg * 0.047 mg/kg-day-1) / 70 kg = 1.1E-04 or 1.1 in 10,000 or 11 in 100,000.
See!  11 times, just like Gradient said in Table 8a!

Yes, but think about it for a minute....

What that ratio of "11" represents is this situation:
  • 100,000 workers using 12 laundered shop towels per day for 9,800 days (245 * 40)
  • 11,760,000,000 laundered shop towels containing an average of 100 mg/kg of lead
  • 100,000 workers placing their hand to their mouth 11,760,000,000 times
Let those numbers sink in...check my math, I could have made a calculation error.

Notice what it would take to get 11 additional cancers in 100,000 workers for 100 mg/kg of lead?  11.8 billion laundered shop towels used, 11.8 billion times the worker's hand contacts the mouth.

Here is what ATSDR says about exposure and cancer, just so you can see that my logic is sound on this.
ATSDR extensively reviews literature linking exposure to compounds with cancer. The lowest level of exposure documented to cause any form of cancer in humans or animals is reduced by a safety factor of 100,000, which simply means if 100,000 people were exposed to this amount ofcompound 24 hours, everyday of their lives for 70 years, 1 extra cancer case might be expected above the normal rate of cancer in that population, i.e. 1 case in 100,000 above normal. (1)
The population here is workers.  So if you can honestly envision 11.8 billion laundered shop towels containing and average of 100 mg/kg of lead after being washed in soap and hot water, then dried under heat, a plausible situation, well I've got a bridge for you to buy!  And if you can see each of these 100,000 worker's bringing their hand to their mouth 11.8 billion times, well I've got land in Florida to sell you as well!

That ratio of "11" times higher than the NSRL uses Gradient's values and equation!

What happens if I use lead intakes calculated using more sound values?   In a previous post I made a case for throwing Gradient's equation out...

...and replacing it with CalEPAs hand to mouth equation.

Guideline for Hand-to-Mouth Transfer of Lead through Exposure to Consumer Products: 2011
The CalEPA equation calculates the daily total intake.  The intake is divided by 70 kg (weight of an adult) to derive a mg/kg-day intake value. (See post)
  • Intake = 0.0013 mg/cm2 x 19 cm2 x 0.5 x 1.5/hour x 8 hours =  0.148 mg per work day
  • 0.148 mg per day = 0.148 / 70 kg =  0.0022 mg/kg-day Intake or 2.2E-03 mg/kg-day
Using Gradient's EF of 245 days, an ED of 40 years, and an AT of 25,550 days (70 years) we would modify the CalEPA calculation as follows:
  • (0.0022 mg/kg-day * 245 days/year * 40 years) / 25550 days = 8.4E-04 mg/kg-day
  • 0.00084 mg/kg-day * 70 kg = 0.06 mg-day
Using CalEPA's hand to mouth intake formula, a worker using twelve laundered shop towels per day for 40 years would have a lead intake of 0.00084 mg/kg-day over a 70 year period of time.

Placing that intake into CalEPA's cancer risk calculation, the "R" cancer risk would be:
  • R = (0.06 mg * 0.047 mg/kg-day-1) / 70 kg =  4 in 100,000.
Using Gradient's values - with the exception of the hand to mouth transfer rate - the excess cancer risk from using 12 towels per day containing 100 mg/kg of lead for 40 years is 4 additional cancers per 100,000 workers.

So whatcha think?  

Is 11.8 billion shop towels with 100 mg/kg lead a plausible scenario?  Will 100,000 workers place their hand to their mouth 11.8 billion times?  Is this really an exposure situation where one would ask a worker who is using a laundered shop towel:  "Why risk it?"
As I stare into that baby's eyes I have no problem telling that dad, go ahead and use laundered shop towels. If lead is the baddest metal they found, go ahead and use a laundered shop towel all you want.  Heck, you can even use it while drinking apple juice!

Next post: Laundered Shop Towels: 14 - Should you believe them?


Thursday, October 6, 2011

Laundered Shop Towels: 12 - Everything gives you cancer...except laundered shop towels.

First, a little bit of background on looking at exposure to carcinogens:
ATSDR recognizes that, at present, no single generally applicable procedure for exposure assessment exists, and, therefore, exposures to carcinogens are best assessed on a case-by-case basis with an emphasis on prevention of exposure. (1)
What this means is that we can provide no real method for dose/response when it comes to exposure to chemicals suspected to be carcinogens.  Therefore "0" exposure is recommended.
ATSDR recognizes that estimation of lifetime cancer risks is further complicated when available data are derived from less than lifetime exposures and that pharmacokinetic insights from animal models may be of utility in addressing this issue. (1)
What this means is that we can look at animal models to help us, but we lack data on a lifetime exposure to chemicals (70 years) so our estimates of a cancer risk will be lacking.
The lowest dose levels associated with carcinogenic effects are identified as cancer effect levels (CELs), with the stipulation that such a designation should not be construed to imply the existence of a threshold for carcinogenesis. (1)
Lowest dose found does not draw a line in the sand where below that is "no cancer" and above it is "cancer."
Also, exposures associated with upper- bound excess risk estimates over a lifetime of exposure (i.e., one case of cancer in 10,000 to one case of cancer in 10,000,000) as developed by EPA are presented. (1)
We look at dose in terms of a cancer risk.  CalEPA looks at a risk of cancer as one in 100,000 (10-5):


CalEPA has developed a "No Significant Risk Level" (NSRL) of 15 ug/day for lead.  What this value is used for is to set a "safe harbor" amount for which the business does not have to post a Proposition 65 warning sign.  It assumes that a person could consume up to 15 ug of lead per day (2.14E-03 mg/kg-day) with out a risk of more than 1 additional cancer per 100,000.  15ug of lead dos not assume a "safe" threshold, it is used to establish an amount of lead whereby a Proposition 65 notification is not required.

When Gradient states that lead exceeded the CalEPA NSRL by "11" times:

(Gradient 2011 Report)

What exactly does a ratio of "11" mean in terms of risk?  Here is what ATSDR says about assessing exposure to a carcinogen:
Both exposure and toxicity information are necessary to fully characterize the potential hazard of an agent. ATSDR considers exposure to an agent to be "an event consisting of contact at a boundary between a human and the environment at a specific environmental contaminant concentration for a specified interval of time; the units to express exposure are concentration multiplied by time."  (1)
Gradient assumes that each time a laundered shop towel is handled by a worker - exposure - there will be intake of the metals that remained on the towel after it has been washed.  That intake is also referred to as a "dose" which ATSDR defines as:
"[t]he amount of contaminant that is absorbed or deposited in the body of an exposed individual over a specified time. Therefore, dose is different from, and occurs as a result of, an exposure."  (1)
In order for Gradient's model to be true, contaminants on the laundered shop towel must be deposited onto the hand and the hand must contact the mouth.  The "dose" will be the amount of contaminant on the hand that is transferred into the mouth.

Cancer risk is looked at differently from chemicals that do not contribute to cancer or cause health effects other than cancer.  Gere is what CalEPA says about exposure to carcinogens:
For chemicals that are listed as causing cancer, the "no significant risk level” is defined as the level of exposure that would result in not more than one excess case of cancer in 100,000 individuals exposed to the chemical over a 70-year lifetime. In other words, a person exposed to the chemical at the “no significant risk level” for 70 years would not have more than a “one in 100,000” chance of developing cancer as a result of that exposure. (2)
How does CalEPA calculate that "no significant risk level” for lead?

Source  Page 15

The "theoretical cancer potency" - qhuman - is also called the cancer slope factor.

For lead, CalEPA uses the value 0.047 mg/kg-day-1 (see graphic at the top of this post).  Plugging in this value into the formula:
NSRL = (0.00001 x 70) / 0.47 = 0.0148 mg or 0.0148 * 1000 = 14.8 ug ~ 15 ug (ppb).
In other words, a person exposed to 15 ug (ppb) of lead for 70 years would not have more than a “one in 100,000” chance of developing cancer as a result of that exposure.

If we agree that 15 ug consumed for 17 years would  show more than one additional cancer per 100,000, what would Gradient's intake of 2.4E-03 mg/kg-day (0.168 mg)?

(Gradient 2011 Report)

In other words, if 15ug lead = 1 in 100,000, what would 0.168 mg lead result in?

Guess I'll need to calculate that.  Dang, more math...and I suck at math.  (Note to past self should time travel become a reality: Take math instead of computer programming in Fortran.)

Next post: Laundered Shop Towels: 13 - 100,000 workers using 12 towels per day