Thursday, April 14, 2016

Risk Assessment Without Numbers

Adam Finkel recently sent me a Commentary from an advanced access publication (January 2016) of the Annals of Occupational Hygiene entitled “Hygiene Without Numbers” by Hans Kromhout.    Adam knows me and knows that I could not read such a piece an NOT comment.

I have never met and do not know Dr. Hans Kromhout, except by reputation, but I found his words to be right to the mark in his two pages of comments which I would be happy to forward to anyone requesting it of me at

Hans Kromhout described control banding as a "numberless intervention" and generally criticized its adequacy.  Indeed, I have always been frankly wary of control banding, which in my opinion, uses available and typically quite limited data to takes educated guesses at the ranges of toxicity to provide the level of needed control at various bands of exposure.  When combined with “exposure banding” one takes a similar banding estimate approach to the level of exposure that might be extant to get some notion of risk.   I CAN see this as the FIRST steps in a process aimed at understanding and controlling risk for a large number of chemicals but, like Dr. Kromhout, I do not see it as the end game.  There is simply too much uncertainty related to underestimation or, on the other side, overestimation of risk and both conditions are unacceptable for obvious reasons.

Everyone wants to “add value” to their organization and be “cost-effective”.  These are well-worn and, on their face, not unreasonable precepts enshrined in our psyche over at least the past 20-30 years especially in Corporate America.  Indeed, I believe that these personal/professional drivers have fed the rush to banding.   The bottom-line for me is that, according to my mother, there is no free lunch.  When one is committed to trying to understand the risk to human health from exposure to the vast majority of chemicals in commerce, we face an enormous short-fall in basic information related to both the toxicity and exposure associated with our interactions with these chemicals in a modern society.  I see banding as a response to the pressures that result from this uncomfortable situation.  As indicated above, I see it is a positive initial move but, I believe, in the majority of cases it does not reasonably or adequately assess the risk.

Risk assessment desperately needs data and the subsequent modeling of that data as the application of the scientific method to interpret that data and adequately estimate the level of risk.   That is, we need data on both the toxicity and exposure which should be accompanied by modeling these data to inform our confident knowledge of and decisions concerning the risk posed.   Like food and water, I believe that, freedom from unacceptable risk to chemicals should be considered to be a human need and its importance and provision should be recognized and addressed as such.

Spending the money to get the “numbers” will be much more expensive than proceeding with banding as the end game; however, it will be “cost-effective” relative to preventing unacceptable exposures and risk (or over-regulation).  This should be an important precept for any general society that truly values both its general economic health and the physical health of its citizens.