When Risk Assessment is a Problem

An experience with a former employer was brought back to the forefront of my mind as I was reading Chapter 14, Quantitative Risk Assessment as assigned. In this particular case, an aerospace manufacturing company was making some process changes, and decided to move their contact cooling water outside and place into temporary containment (read: plastic kiddie swimming pools!) This was perfectly legal back then, in the late 60's. This contact cooling water happened to be contaminated with hexavalent chromium, among other constituents. This worked out well, until it rained and the pools overflowed into the small creek located 40 feet nearby. After a thorough investigation involving sampling and risk analysis conducted decades later, the EPA came back and stated that chromium was deposited in the sedimentary layers at the bottom of the creek, and that it was safest left alone in its current state and undisturbed. The best and safest option in this case, based upon the data and subsequent risk analysis, was therefore to do nothing.

In other cases, there are other reasons to do nothing, as noted by Debra S. Knopman in Waste Site Clean Ups in Slow Motion, PPI Backgrounder Sep 1, 1998: Under the current program, moving contaminated soil kicks in a plethora of RCRA rules--unevenly administered and often disconnected from environmental risk--that too often discourage actual clean up. More predictable regulatory treatment, commensurate with the risk, will contribute to certainty about economic consequences of failing to act responsibly.

Frustrated with a program that appears in many cases to be led by decisions that are arbitrary due to political or social wills provides a difficult environment for site owners, or more importantly potential voluntary disclosures.

Another issue involved in risk assessments of hazardous waste sites involves how EPA classifies a site, and the inherent difficulties created by that classification, as evidenced in this excerpt from the CATO Institute: Privatizing Superfund: How To Clean Up Hazardous Waste by James V. DeLong retrieved January 30, 2008 from http://www.cato.org/pubs/pas/pa-247.html:
(Superfund) protects against risks that might arise if the site were put to use in the future and if all measures to avoid exposure failed. The exposure scenarios used to justify stringent cleanup levels bear no relationship to present uses of the land and do not consider the possibility of restricting future uses. They are based on what exposures might occur in the future if the land were restored to unrestricted use. In other words, the risks that are to be protected against are all hypothetical and easily avoidable. They are not real risks that exist today. "The underlying assumption driving EPA risk analyses is that there will be new residential areas on existing Superfund sites where there are currently no such residential areas."

For example, one of the horror stories used in the current debate over regulatory reform concerns a site in New Hampshire at which the EPA forced the expenditure of millions of dollars to clean up the soil to the point where children could eat dirt 245 days a year. The criticized standard was set, applying the criterion of one in 1 million lifetime risk and using conservative risk assessment assumptions, at a level that would allow children living in homes built on the site to play in their yards… it ignores the more fundamental question of why the EPA insists on making that particular tract suitable for residential use. Industrial or commercial use, or nothing, would preclude dirt ingestion by children, and there is no shortage of residential land in New Hampshire.

In the assigned reading Quantitative Risk Assessment, the author numerous times makes mention that “the methods used in each of the four stages of risk assessment have deficiencies that can introduce a high degree of uncertainty and thus impair the validity of the results”. As a result of this, the risk assessment process is by design overly conservative biased towards public health. Perhaps as the risk assessment process gains more experience and a field of more narrow data, it will become more streamlined and flexible, to closer meet the realities that face the many different types of cleanup sites out there.