We are continually exposed to a mélange of potentially toxic chemicals through the air we breathe, food and water we consume, and products that come in contact with our skin. Some of these chemicals are suspected of interfering with hormone function; causing cancer, asthma or other respiratory harm; damaging the brain and nervous system; and promoting reproductive disorders or negatively impacting developing embryos. More than 83,000 chemicals have been registered by the U.S. Environmental Protection Agency (EPA) under the Toxic Substances Control Act (TSCA) of 1976 for use in U.S. commerce. Most of these substances have not been thoroughly tested for their effects on human health. What's more, we are often exposed to chemicals in various multiple combinations that may produce unpredictable effects.
Some critics say the EPA fails to do enough to protect health and are pushing for reform of the 34-year old TSCA. In recent moves that suggest reform may be closer, the EPA in 2009 issued action plans for compounds that pose serious health or environmental concerns and announced as well the establishment of a "Chemicals of Concern" list. Furthermore, the Safe Chemicals Act of 2010, a bill that would strengthen TSCA, was introduced in Congress this past April; it may be taken up for consideration later this year.
In the meantime, seemingly harmless, ubiquitous products such as glue, weatherproofing sprays, household cleaners and gasoline additives have been causing illness in both workers and the general public for many decades. Paul Blanc, a physician who holds the endowed chair in Occupational and Environmental Medicine at the University of California, San Francisco, discusses the health risks associated with hazardous chemicals found in common consumer products. He is the author of How Everyday Products Make People Sick: Toxins at Home and in the Workplace (University of California Press, 2007), which addresses the following topics, along with many others, in more detail.
[An edited transcript of the interview follows. ]
How do everyday products make people sick?
There are two main issues: how people are exposed making everyday products, and how people are exposed using everyday products. But I think it is also important to remember an important third phase, which is what happens to these products after people are done using them and they are disposed of, recycled or put into the environment. The take-home lesson is that everything is connected to everything, and there is no magic wall that separates or protects consumers from hazards that are otherwise considered industrial hazards or the environment downstream. We have to think about things from cradle to grave.
How are these illnesses discovered? How do you link an exposure to a health outcome?
It gets progressively more difficult because, generally speaking, as you have lower levels of exposure stepping down from the industrial site to the home, and then from the home to the environment, it is more difficult (but not impossible) to make the connections. Often the connection between exposure and illness is made quite quickly and quite obviously early on in the life cycle of these materials. It is not simply that now we're clever enough to identify these things. If you look back in time you can see that often the lag time between the introduction of a new process or product and the recognition of a health risk was pretty rapid, within just a few years in many cases—even for sophisticated new materials. If it is an acute or fairly immediate effect following exposure, it is easier to identify the link.