Volume 21, Issue 1, 1996 March/April 1996

by Ross Hume Hall

Bad science. This term swirled around the International Joint Commission's (IJC) 1992 recommendation to sunset the use of chlorine and chlorine-containing compounds(organochlorines) as industrial feedstocks. The chemical and plastic industries denounced the recommendation. Bad science, they say. Whereas "good" science says the level of organochlorines in the environment poses no threat. No justification for sunsetting.

Science is neutral; but how people use science can be good or bad. The IJC Commissioners arrived at their sunset recommendation using science in a novel way -- at least novel to the chemical industry and the government agencies that regulate the industry, the U.S. Environmental Protection Agency (U.S. EPA) and Environment Canada.

Let's compare the Commissioners' way, which uses all the information science can deliver, with the traditional way the chemical industry and government assess chemical threats to health. Let's see whose use of science is bad.

First, noncontroversial facts: the organochlorines dumped in the environment, if iridescent, would give planet earth a glow. These substances contaminate every square meter of land and sea. They contaminate all foods. You take in traces with every meal. Each day's intake accumulates in body tissues, building to a level any beginning chemistry student can measure. No dispute here. The controversy rises over whether or not this level damages human biology.

A little history explains why the government agencies and chemical industry insist the level poses no threat. The 19th century chemical industry developed methods of assessing dangers of chemicals in the workplace. A factory is enclosed, relatively small. Workers come in contact with a small number of chemicals, easily tracked. Factory dangers are easy to check.

When U.S. EPA and Environment Canada were created in the early 1970s, these agencies thought of the environment as one big workplace. They extended the 19th century methods of assessing worker safety to protecting the public: babies, toddlers, young people, old people, exposed in the wide world to thousands of difficult-to-track toxics.

Why does workplace science fail when applied to questions of chemical threats in the complex world of cities, farms, rivers and countryside? To be more precise, workplace science consists of two sciences: toxicology and epidemiology.

Epidemiology tries to link a chemical exposure to some observed ill. Such a study might ask, for instance, if the level of organochlorines in your food causes declining sperm count. Conducting the study is like using a flashlight to look for a criminal in a dark woods; the criminal in this case is proof of the link. You may or may not find the criminal, but failure doesn't mean no criminal exists.

Likewise, concluding no link exists between organochlorines and declining sperm count or any other human ill based only on an epidemiologic study would be bad use of science. Epidemiology applied to environment/health questions is a weak flashlight of a science.

What about toxicology? Does this laboratory science give more solid information? Toxicologists inject or feed test-chemicals to lab animals, then extrapolate results to people. Rats and mice live short lives and the test chemical that shows no harm in the rodent may, in fact, injure long-lived humans. You can't be sure.

Toxicology suffers an even more serious flaw: one-chemical-at-a-time testing. John Douill, Professor of Toxicology, University of Kansas, speaking at the 1993 IJC Biennial Meeting on Great Lakes Water Quality, admitted toxicology is incapable of assessing mixtures. In the real world, each of us carries hundreds, if not thousands, of organochlorines and other toxics in our body tissues. Toxicology is blind to the dangers of carrying this lifetime burden.

Yet -- and here is a bad use of science -- the chemical industry says: we've applied the two sciences, epidemiology and toxicology, and found no evidence the toxic burden threatens a person's well being. This is a bad use of science, no matter who is doing it, because the house of science has many rooms, many disciplines. Any discipline, whether geology, health statistics, wildlife biology or hundreds of others, can add to our understanding of how organochlorines in the environment damage humans. Toxicology and epidemiology may provide helpful facts, but we can't bind judgements to that information alone. More information is needed to come to sound conclusions.

The IJC Commissioners made their 1992 sunset recommendation drawing upon the entire house of science. Based on the weight of the total body of evidence they concluded the level of organochlorines in the environment and in breasts, ovaries, prostates, testicles and other organs threatens people's wellbeing. The surest way of removing the threat is to phase out organochlorine manufacture.

The sunset recommendation in a deeper sense warns U.S. EPA, Environment Canada and the chemical industry: you can't protect the public basing decisions on two small rooms, epidemiology and toxicology.

If we wish to protect citizens from toxic assault, if we wish to protect generations yet unborn, we have to use all the sciences. We have to base decisions on the weight of all the evidence. Now is such use of science bad or good?

Ross Hume Hall is a writer and consultant on environment and health who formerly cochaired the Health Committee of the International Joint Commission's Science Advisory Board.

Sommaire

La science est neutre, mais on peut l'utiliser à bon ou à mauvais escient. Les commissaires de la CMI ont pris un chemin scientifique novateur pour formuler leur recommandation sur l'élimination progressive du chlore comme charge d'alimentation industrielle - du moins ce chemin est novateur pour l'industrie des produits chimiques et les organismes gouvernementaux de réglementation.

La recommandation d'élimination progressive mentionne qu'il est impossible de protéger le public en fondant les décisions sur deux domaines étroits, l'épidémiologie et la toxicologie. Si nous voulons protéger les citoyens contre des atteintes toxiques ainsi que l'avenir des générations futures, nous devons faire appel à toutes les sciences. Nous devons fonder nos décisions sur le poids de toutes les preuves. Cette utilisation des sciences est-elle alors bonne ou mauvaise?

Revised: 28 February 1997
Maintained by Kevin McGunagle, mcgunaglek@ijc.wincom.net