During a recent afternoon coffee break in our research group at MIT, one of my colleagues mentioned he was taking a break from working in the clean room for the next few months. He explained that he and his wife were trying to have a baby, and that he figured it was probably best to avoid touching chemicals for a while. In typical form, we all joked about discovering the side effects of our everyday lab chemicals later down the road, 20 years from now when we might grow a third arm or get brain damage (a more realistic scenario). But everyone admitted to being clueless about the reproductive health effects of the solvents, resists and other chemicals that we handle on a daily basis as part of our research.
One particular chemical that came up was n-methyl-2-pyrrolidone, or NMP, a solvent that most of us use several days a week for standard nanofabrication tasks like stripping resist, and frankly treat as only slightly more dangerous than water. “I heard NMP makes women infertile,” one co-worker mentioned. “Don’t worry,” another said to me, “The studies only showed infertility for male mice, I think, so you’re good.”
Later on, back at my computer, I scrolled through research papers claiming an alarming set of risks for NMP, including reports of fetotoxicity and reduced fertility in rats. One study attributed a lab worker’s stillbirth to high levels of exposure to the chemical as part of her job. Hoping to find some advice on reproductive risks of other chemicals, I turned to the National Institute for Occupational Safety and Health’s (NIOSH) website. Their page on female reproductive risks offered little comfort, acknowledging that “scientists are just now beginning to understand how reproductive hazards affect the female reproductive system,” and that “most workplace chemicals have not been studied for reproductive effects.”
Taking in this glaring admittance of ignorance, I wondered what other dangers we aren’t aware of. Are the fertility risks different for women like me compared to our male colleagues? And will the chemicals I handle now as part of my graduate work rear their ugly heads in the future, affecting my ability to have children?
“A big misconception in my mind is that people rely on and think that their organization has policies in place that are protective,” says Stephanie Chalupka, a professor of nursing at Worcester State University and visiting scientist at Georgetown University. Chalupka studies risks of environmental and occupational chemical exposures, so I reached out to her to learn how reproductive hazards could be mitigated.
She explains that over 1,000 workplace chemicals have demonstrated reproductive effects on animals, but most have not been studied in humans. Organic solvents, for example, have been associated with menstrual disorders, fetal loss and birth defects in women, as well as reduced semen quality in men. The type, dose and duration of exposures can lead to drastically different results for both sexes. In men, some chemicals can alter the production, shape or genetic composition of sperm.
For pregnant women, exposures during the first trimester can lead to miscarriage or birth defects, while exposures later on during the pregnancy may be associated with neurodevelopmental issues and premature births. Some substances like lead reveal their presence in the aftermath, building up in the mother’s tissue for years until being released later during pregnancy or breastfeeding.
The workplace chemicals with documented reproductive effects account for only a tiny fraction of the 72 million unique chemicals registered by the American Chemical Society, the majority of which have not been tested for reproductive safety. With roughly 15,000 new substances added to the registry every day, the possibility of exposure to chemicals with unknown reproductive risks is constantly increasing.
Although it might seem obvious that a chemical should be tested for reproductive toxicity before being released to the public, most substances are not, and the reasons are, perhaps unsurprisingly, political.
Approximately 40,000 industrial and commercial chemicals, equating to a total production volume of 30,000 pounds per person per year in the United States, are regulated by the Toxic Substances Control Act (TSCA), a piece of legislation dating back to 1976 that remained untouched for 40 years. TSCA has a legacy of being ineffective, giving breaks to chemical companies such as requiring the EPA to account for the financial effects of forcing industry compliance with its regulations. This inadequacy famously led to the EPA’s failed attempt to ban asbestos in 1989 and earned TSCA the reputation of allowing people to be “legally poisoned.”
Although the policy was finally changed when the legislation was amended in 2016, I was shocked to learn that U.S. chemical safety regulations still lag far behind. When I spoke with Veena Singla, associate director of science and policy at the University of California, San Francisco’s Program on Reproductive Health and the Environment, she explained that the European Union has a “no data, no market” policy, where any new chemicals coming into the market must to be accompanied by some minimum amount of toxicity data before they’re allowed. As a result of heavy lobbying by chemical companies during the 2016 TSCA amendment, no equivalent minimum data policy exists in the U.S.
“In our political system, the way it works is those who have more money and more resources have more influence and more power,” Singla tells me. “The chemical industry did not want a minimum data set requirement in the law, so we don’t have one.”
She also explains that although the amendment gave the EPA new authority to request toxicity data from companies to fill in chemical safety gaps, it has yet to order a single test. “In our current scheme, having data is not rewarded. All these chemicals are presumed innocent until they’re proven guilty, so there is zero incentive to fill in more information,” Singla says.
The EPA has also struggled to act on proposed reforms under the new administration. For instance, Singla informs me that NMP, the chemical that first motivated my investigation, was supposed to be banned in certain consumer uses like paint strippers due to its known toxicity. With the change of administration, however, the ban was never finalized.
As a woman in science, I am regularly inundated with questions and concerns about my fertility, usually regarding how to plan having a family around an academic career, and reminders that my timeline is not as flexible as those of my male colleagues. But until I started investigating the risks of a chemical I’ve used heavily for over four years, I never considered that the substances I need to conduct my research could be taking that timeline away from me.
As scientists, we deserve to have the same level of rigor put into testing these chemicals as we put into applying them toward the research that advances our world. As people, we deserve to have legislation in place that protects us from harmful chemicals in the commercial products we use every day. Until those standards are met, we collectively face unknown fertility risks. In the meantime, I’ll be returning to the lab, putting on my clean-room gloves and hoping for the best.