A federal judge on Friday ruled the U.S. Department of Energy violated federal law when it formed a secretive group of researchers to produce a report downplaying the effects of climate change.

The “Climate Working Group” was composed of five scientists hand-picked by Energy Secretary Chris Wright shortly after the White House dismissed more than 400 scientists working on the sixth National Climate Assessment. The group’s July report, “A Critical Review of Impacts of Greenhouse Gas Emissions on the U.S. Climate,” breaks from broad scientific consensus and questions the severity of global warming.

But Judge William G. Young of the U.S. District Court for the District of Massachusetts said the group failed to meet the requirements of the Federal Advisory Committee Act, a 1972 law governing federal advisory groups that requires public meetings, open records and other acts of transparency. Records released under the judge’s orders indicate the group met in secret at least 18 times.

“These violations are now established as a matter of law,” Young wrote in his four-page decision.

The Energy Department had argued the Climate Working Group was not subject to those requirements because it was “assembled to exchange facts or information with a Federal official.” It also argued the claims were moot because the group was disbanded shortly after the lawsuit was filed.

The judge disagreed, noting the group provided policy advice and recommendations to the Department of Energy. The five members of the group included John Christy, Judith Curry, Steven Koonin, Ross McKitrick and Roy Spencer, scientists and researchers who question prevailing climate science and policy.

Among its conclusions, the July report from the group maintains carbon dioxide-induced global warming “might be less damaging economically than commonly believed,” and that “aggressive mitigation policies” — such as those designed to curb the use of fossil fuels — “could prove more detrimental than beneficial.”

The report was widely condemned, including by more than 85 U.S. scientists and experts who published a withering 459-page document denouncing it as biased, error-ridden and unfit for guiding policy. The lawsuit was brought by the nonprofit Environmental Defense Fund and the Union of Concerned Scientists, a national group of about 250 scientists and experts.

“The court confirmed today that the process for this sham report, which was conducted in secret by five known climate contrarians, violated the law,” said Gretchen Goldman, president and chief executive of the Union of Concerned Scientists, in a statement. “The public deserves transparent climate policy decisions rooted in the best available science advice from credible experts.”

In a statement provided to the Los Angeles Times, the Energy Department said it was pleased the judge had denied a request that would have prevented the agency from using the report or keeping it online.

“The activists behind this case have long misrepresented not just the actual state of climate science, but also the so-called scientific consensus,” said department spokesman Ben Dietderich. “They have likewise sought to silence scientists who have merely pointed out — as the Climate Working Group did in its report — that climate science is far from settled.”

The U.S. Environmental Protection Agency also leaned on the report in its controversial proposal to repeal the endangerment finding, a landmark 2009 determination affirming that planet-warming greenhouse gases pose a threat to human health and the environment. The endangerment finding forms the foundation of much of U.S. climate policy.

Erin Murphy, senior attorney with the Environmental Defense Fund, said in light of Friday’s decision the EPA “must immediately withdraw its fundamentally unlawful and forever tainted proposal to repeal the Endangerment Finding, which would impose high costs on the American people who are already experiencing the impacts of pollution-fueled fires, flooding, higher insurance costs, and rising energy costs.”

The lawsuit named the Environmental Protection Agency as a defendant. However, the judge on Friday dismissed the EPA from the suit, writing that he had found “no persuasive evidence” that the agency violated the advisory committee law.