Mind, DisruptedPhoto
AboutThe ParticipantsThe ProblemFindingsToxic ChemicalsPolicy RecommendationsThe ScienceResources

Why Are Human Bodies and
the Environment Contaminated
with Toxic Chemicals?

The Toxic Substances Control Act (TSCA) of 1976 is the primary federal policy intended to protect the public from hazardous chemical exposures. But TSCA is outdated and ineffective. Contrary to popular belief, chemicals do not have to undergo basic testing of their health effects and safety prior to going on the market.

“I feel like I’m in a vacuum,” states Ann WingQuest, participant with cerebral palsy who lives in Alaska, “because I don’t know the manufacturers and I have no way of telling them that they need to be more careful about the chemicals they put in their products.”

We know little about the neurodevelopmental and other health effects of the 82,000 chemicals registered for U.S. commerce today. Roughly 7% of chemicals in use have been subjected to testing thorough enough to determine developmental or reproductive toxicity.20 Given the enormous number of untested industrial chemicals in use, the total number of neurotoxic chemicals in commerce is likely to be substantial.

What We Don’t Know About Chemicals


Note: Graph provided by the LDDI Scientific Consensus Statement

“My body is my life,” states Cathy Ficker Terrill, ”and just as the government regulates the banking industry, they have an obligation to regulate the poisons and toxins in our environment. For many years they knowingly dumped poisons in our rivers and lakes and other waterways. I also believe that these toxins are causing some of these high rates of disabilities. We don’t even know what the effects are on our bodies or the long term effects to the public are.”

At present TSCA does not adequately regulate and control chemicals to prevent harm. Standard toxicity testing does not predict the effects of very-low-dose, cumulative, or synergistic chemical exposures. We need to update federal law in a way that reflects the science of the past 34 years.

For example, scientists discovered that a major tenet of toxicology — that the biological impact of exposure to a chemical is proportional to the size of the dose (or “the dose makes the poison”) — is not always true.92,93 Put another way, exposure to very small doses of some chemicals appears to have a greater impact than slightly larger doses. This effect seems most consistent with hormonally active chemicals, such as BPA, hexachlorobenzene (an organochlorine pesticide), and DEHP (a chemical in a class of multifunctional chemicals called phthalates, which are used in a wide array of consumer products and industrial processes).94

doctorScientists have also moved forward in considering all the factors that impact the body’s capacity to withstand exposures to toxic chemicals. For example, a report by the National Research Council (NRC) of the National Academy of Sciences (NAS), “Phthalates and Cumulative Risk Assessment,” is calling for a better assessment of cumulative risk factors which can modify the effects of any toxic chemical. Cumulative risk, in a broad sense, means, “the risk posed by multiple chemicals and other stressors that cause varied health effects and to which people are exposed by multiple pathways and exposure routes and for varied durations” — in other words, stress, nutrition, gene-environment interaction, exposure to infectious agents, and other factors can modify the effects of toxic chemical exposures on an individual or a community.95

The NRC report also calls for considering exposures to all chemicals associated with common adverse health outcomes, rather than simply considering chemicals that operate by similar mechanisms in developing risk assessments. For example, the report suggests, “EPA could evaluate combined exposures to lead, methylmercury and polychlorinated biphenyls because all contribute to cumulative risk of cognitive deficits consistent with IQ reduction in children, although the deficits are produced by different mechanisms of action.”95 Doing so, the report concludes, would reinforce EPA’s capacity to fulfill its mandate of protecting human health.

A 2007 report commissioned by the EPA and written by the NRC proposed a paradigm shift that would greatly improve “how scientists evaluate the health risks posed by potentially toxic chemicals found at low levels in the environment. These advances would make toxicity testing quicker, less expensive, and more directly relevant to human exposures.”96

The report overview conceded that such a shift would “require a substantial commitment of resources, the involvement of multiple organizations in government, academia, industry, and the public, and… take time (10–20 years) to achieve.”96

In order to develop and implement effective toxicity testing, we need the federal government to demonstrate a strong, sustained commitment to chemical policy reform.