A drug manufacturer used the same uncleaned equipment to make pesticides as it did several human drugs, according to a warning letter released by the Food and Drug Administration. The result was that at least two medicines were contaminated with pesticides, the agency noted.

The FDA’s sternly worded letter charged that drug manufacturer Product Quest MFG, LLC of Daytona Beach, Florida, and its manufacturing facility, Ei LLC in Kannapolis, North Carolina, committed “significant violations.” It also noted that the firm’s response to the problems so far were “inadequate” and that its investigations into the extent of the problems were “not thorough and scientifically sound.” The agency levied legal threats if the issues weren’t fixed pronto.

“Failure to promptly correct these violations may result in legal action without further notice including, without limitation, seizure and injunction,” the letter stated. The agency also threatened to deny the manufacturer’s drug applications, contracts, and block its drug export certifications.

Neither Product Quest nor Ei immediately responded to Ars’ request for comment.

On its website, Product Quest notes that:

Quality is not a goal to be achieved or a score on a report—it’s a way of operating. It’s evident in our state-of-the-art facilities and strength in both regulatory and customer audit performances. It’s delivered through our corporate integrity and higher-than-industry standards, which result in exceeding our customers’ expectations every single day.

Likewise, Ei, which was acquired by Product Quest in 2013, said on its website that “in a very real sense, quality is our product.”

The FDA seems to disagree. It noted that Product Quest “manufactured topical human drugs and several pesticides in the same building, using shared equipment,” which were not adequately cleaned to prevent cross-contamination. That contamination could cause pesticides to make their way into human drugs and for different human drugs to contaminate each other, the agency said.

During its investigation, the FDA found records indicating that two unidentified human drugs made by Product Quest had been contaminated with a pesticide, the name of which was redacted. The medicines were manufactured on the same equipment as the pesticide. The agency also noted instances when the drug maker failed to investigate other contamination issues. In those cases, two human drugs—erythromycin pledgets, a topical antibiotic, and clobetasol propionate, a corticosteroid spray—were found to contain “unknown impurities.” Documents suggested that dirty equipment was again the cause, but the FDA said the drug manufacturer didn’t do any follow-up to figure out what happened to prevent it from happening in the future.

“[Product Quest] continued to use the same equipment for commercial manufacturing after [it] detected the impurities, potentially cross-contaminating other products,” the FDA wrote.

Product Quest has 15 days from the receipt of the letter to respond to the FDA.