What happened: In late 2019, scientists at the Environmental Protection Agency (EPA) concluded that the chemical trichloroethylene (TCE) was unsafe because it can deform the hearts of fetuses, even at low levels – but when the draft reached the White House for review, political officials made far-reaching changes, including direct edits, that downplayed this finding. The altered evaluation dismisses years of scientific consensus that TCE, which is used by companies and consumers to degrease metal and remove stains, is linked to heart defects.
Why it matters: When political officials sideline the findings of EPA scientists, as happened for TCE, it undermines this science and obscures serious threats to public health. The public depends on federal agencies’ risk evaluations, which form the backbone of policy decisions. EPA’s chemical evaluations, for example, help determine if, how, and to what extent a chemical could pose a serious risk to human health, and whether the EPA should control or stop its use and manufacture. This impact underscores how crucial it is that these evaluations are founded on the best available science, and for TCE, political interference in the science could set the stage for continued use of a dangerous chemical.
When scientists at the Environmental Protection Agency (EPA) concluded in a risk evaluation that the chemical trichloroethylene (TCE) caused fetal heart defects, even at low doses, political officials at the White House overrode their findings.
Scientists have known for decades that TCE is dangerous. At high doses, the chemical – a sweet-smelling liquid used in stain removers, aerosol degreasers, and lubricants – has been linked to a range of illnesses, including liver, kidney, and testicular cancer; leukemia and lymphoma; and immune diseases like lupus. However, because these outcomes are most strongly associated with high or chronic exposure to TCE, workers and consumers have been permitted to use the chemical with certain restrictions.
But scientists have also long identified a serious outcome that can occur with low levels of exposure: fetal heart defects. In 2003, researchers published a landmark study that found that even trace amounts of TCE led to “cardiac malformations” in developing rat embryos, such as missing coronary arteries and valve defects. Since then, more than a dozen animal studies have corroborated these findings, and human epidemiology studies suggest that TCE also causes these defects in humans, leading to infant hospitalizations, emergency surgeries, and sometimes death.
In 2011, the EPA conducted a toxicological review for TCE and concluded that the chemical, including its impact on fetal hearts, was dangerous. Based on this evidence, in the last few weeks of the Obama administration, EPA officials proposed a ban on several uses of TCE to limit human exposure.
Under the Trump administration’s EPA, the proposed ban was quietly buried. Nevertheless, in December 2019, the EPA’s Office of Chemical Safety and Pollution Prevention (OCSPP) wrote a draft risk evaluation on TCE, which used fetal heart defects as the baseline for determining unsafe exposure levels – a health-protective finding that aligned with scientific consensus. Given that fetal heart malformation “is the effect that is most sensitive [to TCE exposure],” the draft reads, “it is expected that addressing risks for this effect would address other identified risks.”
However, when the draft reached the White House for review, officials at the White House’s Executive Office of the President (EOP) altered these findings. In unsigned emails and anonymous redline edits, officials directed the EPA scientists to discard the science on TCE’s role in fetal heart defects. The EOP version acknowledges that several studies have linked TCE with fetal heart defects but notes “uncertainties which decrease EPA’s confidence in this endpoint.” The White House contends instead that immunosuppression should be the main “[driver] for EPA’s determination of unreasonable risk” – a major deviation from the scientists’ findings. The White House also deleted all 322 instances of the phrase “cardiac toxicity” from the draft risk evaluation and increased mentions of “immunosuppression” more than 30-fold.
The ramifications of this political interference are immense. TCE is still used extensively in consumer and industrial contexts, and the chemical persists even where use has subsided: Research shows that TCE leaches into groundwater and contaminates the drinking water of 14 million Americans. It has been found on 1,400 military bases and nearly 800 Superfund sites, and babies born to mothers who live near TCE-emitting facilities are at increased risk of congenital heart defects. By burying the science on TCE’s danger, the EPA may be paving the way for its continued use, and protecting industry from the enormous liability of cleaning up this unsafe chemical.
On February 21, 2020, OCSPP’s “official” risk evaluation – which scrapped fetal heart defects as a baseline for TCE’s risks – was released for public comment. By sidelining EPA scientists and eliminating a key scientific conclusion based on the best available science, the White House puts the public’s health at risk, especially the health of the nation’s most vulnerable.