A former top government environmental health official joined health experts on Wednesday in expressing alarm as the Trump administration moves forward with a proposal that scientists say would upend how the U.S. regulates threats to public health. “It will practically lead to the elimination of science from decision-making,” said Linda Birnbaum, who retired last month as director of the National Institute of Environmental Health Sciences after serving under both Republican and Democratic administrations. In an appearance before the House Committee on Science, Space and Technology, Birnbaum said the proposal could be used to roll back fundamental protections from air pollution and other toxins. The “effects here could affect an entire generation,” she said. The Environmental Protection Agency’s proposed regulation seeks public disclosure of the data underlying studies used by agency officials in deciding how to regulate contaminants and toxins, from car exhaust to coal waste to pesticides. Opponents fear that could include seeking to release identifying information for patients and study participants in violation of confidentiality requirements, leading important public health studies and other research on people to be taken out of consideration instead. The administration says the proposal would increase transparency in government regulation. Jennifer Orme-Zavaleta, an EPA principal deputy assistant administrator, told the lawmakers that the agency was working 'to ensure the public has access to information so they can make decisions to protect their health and environment.” But opponents fear the measure will be used to toss out findings of decades of research on humans — and of future studies yet to come — that are a foundation of environmental and public health regulation. With weaker evidence regarding risks to human, the result could be weaker regulation of toxins, opponents said. When the EPA first raised the proposal last year, university heads, public health officials, researchers, health workers, environmental advocates and others lined up at the agency’s public hearings to object. The agency received nearly 600,000 public comments on the change, the majority urging against it. Debate on the proposal revived this month when the EPA sent a draft supplement to the measure to the White House for government review. That made clear that the administration was moving ahead on the measure despite the unusually strong torrent of opposition from scientists and health practitioners. At Wednesday’s hearing before a committee of the Democratic-controlled House, some Republicans also indicated concerns about the measure, which follows past, failed efforts by conservative lawmakers to get similar legislation through Congress. “This is about attacking the EPA under the current administration — not about improving transparency and scientific integrity,” said Rep. Frank Lucas of Oklahoma, the committee’s senior Republican member. Lucas called the EPA proposal “well-intended,” but said broader discussion was needed about “the best way to improve reproducibility and transparency.” Orme-Zavaleta, a career EPA employee, said a draft of the rule obtained by the news media this week was not the final version. Under questioning from Democratic lawmakers, Orme-Zavaleta acknowledged that while the proposal was not intended to be retroactive to existing rules, it could apply to past health studies. Democratic lawmakers argued the change could also be used to throw out findings of health studies and rewrite regulations whenever an existing rule comes up for review. “The true purpose is to undermine the decades of sound science on which the EPA relies to protect public health,” so that “political agendas are given more weight than science,” said Rep. Paul Tonko, D-NY. It “will endanger the safety and health of millions of Americans for many generations to come.” Rep. Bill Foster, D-Ill., noted the early draft rule would allow the EPA administrator to make exceptions to the data disclosure requirements. “Can you understand why we might not be comfortable having the final call being made by a coal lobbyist?” Foster asked, referring to the current EPA administrator, Andrew Wheeler. Birnbaum, one of five scientists and health experts testifying Wednesday in addition to the EPA official, said eliminating studies and research on humans because of the confidentiality of identifying information would leave regulators more dependent on animal studies, which are less accurate for people. However, Wheeler announced separately in September that the agency intended to scale down and ultimately eliminate testing of chemicals on animals. Animal rights advocates welcomed the move, but health officials said it eliminated an essential safeguard for human health.