70 Chemicals and Growing


Mankind has found and developed over 100 million unique chemical substances and the rate of discovery is rapidly increasing, but without a corresponding increase in knowledge of their environmental and health implications. That hasn’t stopped the use of many of these new chemicals in the new technology that enables many of the comforts of the modern age.


Despite high demand for these new chemicals only around 85,000 are listed in the Toxic Substances Control Act of 1976 (TSCA) inventory, which the Environmental Protection Agency (EPA) uses to choose which chemicals to study and regulate. This pyramid gets only narrower from there: Of these 85,000 substances, only around 150 have recommended water quality guidelines in our surface waters, and only 40 of these compounds have legally enforceable limits.

If we measure regulation in terms of rates over time, we’ll still find that chemical regulation and assessment lags far behind chemical discovery: over the last 50 years, on average, one substance has been registered in the Chemical Abstracts Service (CAS) every 2.5 minutes, while, between 1979 and 2015, TSCA’s inventory has grown by only about one chemical per day. Can we find a cure to our chemical dependence under TSCA and its reform? Should we look elsewhere to review and regulate our chemicals?

The simple fact that we use and are reliant on a rapidly growing number of chemicals is not reason enough to issue regulation: exposure to a chemical is not the single determinant of health risk. Rather, health risk is driven both by exposure and toxicity. Conducting experiments to calculate the “dose-response” curves necessary to integrate both exposure and toxicity is difficult and time-consuming. Thus when thousands of chemicals make their way into the market every year, the iterative, multi-disciplinary process to determine safe and definitive exposure levels lags far behind.

But, science aside, TSCA’s registration of chemicals is weak, and its regulatory speed is far outpaced by the rate of synthesis and implementation of new chemicals by industry. The root of this problem is multifarious, stemming from TSCA itself—continuing to be the law of the land without substantial change since 1976—and a series of events after the act’s passing. Regarding TSCA itself, the EPA cannot conduct swift enough safety assessments on the majority of new registered chemicals due to a complex regulatory framework.

Companies need only submit a “pre-manufacture notification” and do not need to include any toxicity information. But, for the large majority of chemicals registered that were in use before 1976, the EPA must prove that these compounds are of “unreasonable risk of injury to health or the environment” in just 90 days. This shifts the burden of proof from industry to the EPA, which as a governmental agency, is meant to serve the public’s interest. Thus, within this regulatory set-up, these chemicals are presumed to be safe, even without sufficient toxicological information. And, even if adequate information does exist on a chemical to prove unreasonable risk, the process for issuing regulation has proven to be laborious and costly.

Furthermore, if a regulation is proposed, it must be the “least burdensome” (i.e. the least costly) option. Additionally, due to a clause within TSCA, companies often do not have to disclose confidential business information, meddling with the public’s right to know about the chemical background of products that may even enter their very households. All of these high-level regulatory issues are also exacerbated by major budget restrictions imposed on the EPA in the 1980s, changing political leadership, and industry success in limiting the EPA’s authority in offering regulation.

To try and alleviate many of these problems, Senator Vitter of Louisiana and Senator Udall of New Mexico co-sponsored a bill to reform TSCA, and received bipartisan support from the Senate. In the House of Representatives, a companion bill was passed in June 2015, although the committee continues in Senate.

Notably, the reform lessens the high burden of proving “unreasonable risk,” gives the EPA more jurisdiction in determining an appropriate regulation, and allows the EPA to evaluate chemicals on a purely health-based standard for those they anticipate to be the most vulnerable populations, such as pregnant women and young children. The bill also details that the EPA must list 10 chemicals for which it will conduct three-year exposure assessments in the bill’s first year of enactment, 10 more three years later, and five more after that. Some critics of the bill find most of their disagreement here.

The EPA will only evaluate chemicals at a modestly faster pace than it currently does, and will probably not exceed the specified 10 chemicals every three years, due to budgetary constraints. Many also point to the bill’s apparent weakening of state-level efforts: state-level regulation of chemicals is effectively frozen until the EPA places the chemical on its priority list and specifies the scope of its safety assessment. Minor amendments to the language of the bill to alleviate some of these issues and garner the support of more senators continue today.

In just the few minutes it has taken you to read this article, 70 new chemicals have been added to the CAS inventory. And this rate is unlikely to slow given that our industrial products, technology and infrastructure continue to demand the creation of novel chemical substances. It seems unlikely that the EPA alone will ever be able to keep up with this rate of development, let alone cope with the existing backlog of millions of untested chemicals.

To this end, some propose that developing partnerships between the EPA, academic institutions, and professional societies could expedite the review and regulation of chemicals of concern even while TSCA remains unchanged. Moreover, partnerships of this kind could introduce new and improved testing guidelines and utilize the input of thousands of other scientists—not just toxicologists—to assess risk.

Going beyond Washington, the wider academic and scholarly community could generate independent reviews without the conflicts of interest that industry information presents. Once TSCA is finally fully reformed and enacted, these partnerships would continue to be invaluable in ensuring that chemicals continue to benefit society, without harm.

Image courtesy Wikimedia Commons. Originally published by S&S on December 2, 2015.


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