In its first year in office, the Trump administration introduced a solitary new environmental rule aimed at protecting the public from pollution. It was aimed [at] dentists. About 5 tons of mercury, a dangerous toxin ... are washed away from dental offices down drains each year. In Trump's first day in the White House, the administration told the Environmental Protection Agency (EPA) to withdraw an Obama-era plan that would require dentists to prevent this mercury from getting into waterways. But in June, the rule was unexpectedly enacted. This apparent change of heart followed legal action filed by green groups, part of a cascade of courtroom standoffs. In July, a federal court ruled that the EPA couldn't suspend rules designed to curb methane emissions from new oil and gas wells. This was followed by a hasty retreat in August when the EPA agreed to not delay new standards to reduce smog-causing air pollutants, the day after 15 states and environment groups sued. Then, in December, a federal court told the EPA it couldn't delay a new standard for dangerous levels of lead in paint and dust. Many of these legal problems have stemmed from the sheer pace of the rollbacks - required public comment periods have been set aside in some cases, any rationale for repeal or delay has been missing in others. Opponents of the administration also believe there is a determination to expunge every vestige of Obama's environmental legacy, regardless of merit.