Sunday, May 17, 2015

Is Human Health Risk Assessment the Best Tool to Make Decisions?

Human health risk assessment has a bad reputation in some minds. Dr. Peter Montague is an intelligent and articulate thinker, he also pretty much disparages Human Health Risk Assessment, especially the quantitative aspects of it.    The following quote from his writing more than a few years ago struck me the hardest, as I believe it was designed to do:
“Risk assessors are now in the position of the conductors and engineers who kept the trains running on time to the death camps in Nazi Germany to minimize discomfort to their passengers -- they are just doing a job, honorably and to the best of their ability, but the final result of every professional risk assessor's work is the destruction of the natural environment, one decision at a time, and the relentless spread of sickness throughout the human and wildlife populations.”  
If you want to check the entire article to determine the complete context of this quote it is available online at:
In another online essay Dr. Montague asserts:
“Risk assessment is one way of making decisions, but it is not the only way, and it is not the best way.[1] Furthermore, risk assessment as usually practised is unethical.” 
The online reference for this complete opinion piece is: 
It would appear that Dr. Montague believes that we ought to abandon risk assessment in favor of what has been known as the “precautionary principle”.   My read of this principle in its more drastic manifestation suggests that chemicals should be banned (without the benefit of rational risk assessment) if they pose a potentially substantial but relatively uncertain probability of harm from their use and subsequent exposure.
A remarkably thoughtful and articulate defense of risk assessment was put forth by my friend and colleague, Dr. Adam Finkel.    In a published debate with Peter Montague, Adam provides all the reasons I might need to continue to view human health risk assessment as the best way forward.  Please forgive my open admiration for this remarkably powerful and intellectual argument in which Adam defends the rational scientific framework provided by risk assessment while admitting that we have a lot of work to do.   The online reference for Adam’s complete treatise is:   I urge you to download it.
I am reminded in all of this of Winston Churchill’s remarks in 1947: 
     "Democracy is the worst form of government, except for all               those other forms that have been tried from time to time."   
This is how I see risk assessment as a process.
As I have written here previously, uncertainty is the bane of the risk assessment process.  Large error bands (displayed or hidden) in our analyses drive controversy depending on which side of the political or ideological fence you reside.  We have demonstrated that we are fully capable of both over and under-regulating chemical exposures presumably based on risk assessment.   The real task is to shrink those error bands to provide more confident knowledge to feed rational decision.  That means committing the resources to develop the science. 
I believe that it FIRST means that we should acknowledge the size of the error bands while informing the best decisions we can with the always imperfect information in hand.
In my opinion, the authorities who set exposure limits are afraid to admit the current level of uncertainty that exists today.  To date, they have summarily dismissed all calls to do quantitative analysis of exposure limits for non-carcinogens, saying that it is either not possible or meaningless. 
I believe that this condition of not fully disclosing uncertainty also exists, but to a substantially lesser degree, in the realm of exposure assessment.
Unless or until we face up to quantitatively disclosing these uncertainties of our risk assessments to the various stakeholders, I believe that progress will continue to be slow and risk assessment will remain a legitimate target of criticism from both the left and the right.   
In any event, I believe that risk assessment will remain the "worst" tool for making decisions about the risks of chemical exposure to human health, except for all the other approaches.



1 comment:

  1. Much of the appeal of the precautionary principle resides in its conservative assessment approach based on an objective evaluation by a group of subject matter experts often in a rapid and flexible manner if needed. This harkens back to the earliest days of toxicological investigations by Dr. Harvey Wiley and his Poison Squad. Conceptually, quantitative risk assessment is a superior approach with its uniform structure to collect, document and evaluate available information in a transparent manner. However, operationally, risk assessment is often bogged down by the failure of decision makers to use the results as a tool to make a decision. In the face of misguided criticism to permit acceptable exposures in the environment, decision makers wilt, disavow the results or require additional studies which most often do not change the results of the original risk assessment. Regulatory decision making is not based solely on the risk assessment but also must reflect risk management options which are often dictated or constrained by statutory requirements. Risk assessment never was intended to be the precision instrument desired by its critics