These safe harbor levels do not preclude the use of alternative levels that can be demonstrated by their users as being scientifically valid. A hyperlink is provided for those NSRLs or MADLs for which the documentation of their derivation is electronically available. (source)
That hyperlink acknowledges that there is information regarding a "derivation" from the established values written into law.
You will notice that there is no hyperlink for acrylamide and cancer. There is a document  the one I have been using  but California doe not link it. That document states this:
If it were me advising Starbucks et. al. I would have told them to do the following.
 Find out the actual (statistically valid) concentration of acrylamide in YOUR coffee.
 Find an adequately researched and recognized institution that claims a lower Cancer Slope Factor for acrylamide
 Calculate the highest amount of acrylamide seen in the largest dose (cup) of coffee a customer can order.
These safe harbor levels do not preclude the use of alternative levels that can be demonstrated by their users as being scientifically valid.Here's how I would do it using new data that I consider valid and demonstrated.
Based on what we know about the average amount of acrylamide in all coffees, we can assume the following for Starbucks:
Using the NSRL established in the March 2005 document, only the Venti would exceed the NSRL. And if "1" is a cancer risk of one in 100,000 and therfore, according to California, a "No Significan Risk Level, what happens when the amount of acrylamide in a Venti is 1.6 micrograms?
Let's go back to my Excel sheet and see if we can calculate the risk when we know the concentration of acrylamide in a Venti cup of coffee:
Okay, so using the Cancer Potency and the NSRL established in the March 2005 document, the added risk of cancer would be and additional 1.3 per 100,000. Since a one in 100,000 is considered a No Significant Risk Level, then are concern is for cancers over the one in 100,000, in this case we would say that we have a risk to consider of 1.3 additional cancers in a population of 100,000.
Remember, as California tells us...:
Cancer now occurs in nearly one out of every four individuals.
So by drinking a Venti each day for 70 years you jump from 25% to 26.3 percent.
But all of that assumes that the Cancer Potency California came up with is accurate. That is, is 0.7 a valid number and better than any other numbers that could be generated?
Let's take a look, shall we?

Source 
Since acrylamide induced tumors at multiple sites in male and female rats, combined potency estimates were derived for each experiment using Monte Carlo analysis for those tumor sites judged to be associated with exposure to acrylamide. For each tumor site, a distribution of estimates corresponding to the 0.1 through 99.9 percentiles of the linear term (q1) of the multistage model was generated...If  IF  those rat studies are valid, then the actual number is somewhere in that bell curve. Again, since they force the line linear with 0 as the risk and concentration, the Cancer Slope Factor is questionable. But since its all we got, let's roll with it.
Now if you are not familiar with statistics and bell curves, you need to know this. Between two standard deviations from the mean value (the highest peak in the bell curve) lies 95% of all the numbers it could be. COULD be.
California  to be safe  uses the upper 95% value which is two standard deviations to the right of the mean. That number is 0.70. Where have I seen that number before?
If I were advising Starbucks et. al. I would now get fired because everyone listening to me is bored and falling asleep. Still, I soldier on! I yell:
"If 0.70 is valid, well so is 0.20 because (pant! pant!) both of those number have an equal chance of being the real number with a 95% confidence. I mean...if you are going to say 0.70 is the number you can also say 0.20 is the number. Why do you get to pick the upper when the lower is just as valid?"Now if the judge could channel King Solomon, he might say "Enough you two! Let's cut that baby in half  0.50 looks pretty close to the peak  50% for you and 50% for the state."
Aha! the judge fell right into my trap! I can support that number of 0.50. And if I can support it because California does not...
...preclude the use of alternative levels that can be demonstrated by their users as being scientifically valid.,,,Then I win for Starbucks et. al. provided the judge agrees with my work.
So the question is, what makes 0.50 a number that you were hoping for Bowman? Well, let me show you...
EPA IRIS Acrylamide 
I think I could make a persuasive argument that the EPA IRIS presents "levels that can be demonstrated by their users as being scientifically valid."
So if I were to present 0.50 as the Cancer Potency (aka Slope), the my NSRL becomes...
And when we look at the estimated amount of acrylamide in a Starbucks coffee:
Close...but not out of the woods yet. This is why you need to know how much acrylamide is in a Venti. Why they did not go through this is beyond me. Had the amount of acrylamide been similar, they could have fallen back on their original defense. Had it been lower, they could have said "our coffee presents a NSRL for acrylamide."
Now, if I could get the judge to accept 0.50 as the Cancer Slope, the amount of acrylamide is above the NSRL of 1.4 micrograms per day by only 0.20 micrograms, which presents an additional risk above one in 100,00 as follows:
An additional 0.14 per 100,000 cancer risk for drinking a Venti every day for 70 years. I think I may have had a shot at this if I did not bore them to death.
Next Post: Coffee, Acrylamide, and Proposition 65  Part 9  The End!