Stop us if you’ve heard this one before: A senior Trump administration official has been caught influencing the regulation of a harmful substance that he once made money from selling. David Dunlap, a former chemicals expert for Koch Industries, is now a high-level official at the U.S. Environmental Protection Agency. Due to his past employment, Dunlap agreed to recuse himself from any EPA discussions concerning formaldehyde—seeing as Koch is the chemical’s biggest producer. But recently released documents show that Dunlap did participate in such conversations around formaldehyde—conversations held right before the agency canceled the official assessment of formaldehyde’s safety. (In fact, Dunlap signed the recusal the very same day of the agency’s decision.) As Politico reports, the assessment (something chemical giants had been lobbying against for years) would have confirmed formaldehyde’s link to leukemia and other ailments.