"With regard to wastewater management we are subject to a variety of federal, state and local regulation and oversight," said Joel Green, Upsher-Smith's vice president and general counsel. "And we work hard to maintain systems to promote compliance."
Baylor University professor Bryan Brooks, who has published more than a dozen studies related to pharmaceuticals in the environment, said assurances that drugmakers run clean shops are not enough.
"I have no reason to believe them or not believe them," he said. "We don't have peer-reviewed studies to support or not support their claims."
Associated Press Writer Don Mitchell in Denver contributed to this report.