Alerted by the disturbing USGS report and related findings, public agencies and community groups began educational campaigns to discourage people from dumping drugs into trash or the toilet, instead taking them to hazardous waste facilities, or to pharmacies willing to accept them. That’s when the conflict with federal drug control laws came to the fore.

“If you knowingly possess controlled substances, you are potentially liable, so many [people] are afraid,” said Jen Jackson of EBMUD, who has been working with people in other local, state, and federal agencies, including police authorities, to find a way out of the predicament. She is an organizer for a statewide “No Drugs Down the Drain” campaign (www.nodrugsdownthedrain.org).

Some pharmacies will take back prescription drugs (except those containing controlled substances). Many of these, as well as scheduled take-back events and other disposal sites, are listed on the website of the nonprofit Teleosis Institute (www.teleosis.org), as well as on other sites, including that of Save the Bay, which entreats: “Don’t medicate our bay!”

Practices at local hazardous waste facilities vary. The City and County of San Francisco had been accepting prescription drugs for disposal at its hazardous household waste facility for 16 years without running into problems, according to Marjaneh Zarrehparvar, residential toxics coordinator for the City’s Department of the Environment. In 2007, an attorney warned that it might be violating federal drug-control law and exposing contractors to liability if it took in any controlled substances. The City shut down its take-back program and told residents who brought in drugs to take them back home and keep them in a safe place until something could be worked out with the DEA. The program has not resumed.

At some other hazardous waste facilities a “don’t ask” policy seems to prevail. Publicizing that they are not permitted to accept controlled substances, they count on people to bring in only legally acceptable medications.

“It’s kind of a tricky business right now,” said Linda Brown, hazardous waste program coordinator of the northern California region for the Philips Service Corporation, which collects hazardous waste from facilities in all nine San Francisco Bay Area counties, ships it to Kent, Washington, to be consolidated with waste from elsewhere, then sends it to Argonite, Utah, to the company’s Clean Harbors incinerator. (California does not permit incineration because of air quality concerns.) “We state that it’s not in our permit to accept controlled substances. We don’t want residents to bring these in. If some do come, we don’t know.”

The City of Los Angeles conveys a clear message. Its N3D (No Drugs Down the Drain) poster features a photograph of an unhappy-looking woman pouring tablets down the toilet, watched by three disapproving children. A circle with a slash is superimposed. The City is collaborating with Los Angeles, Orange, and San Diego Counties. “We’re trying to figure out how to work with the DEA,” said Timeyin Dafeta, principal environmental engineer with the Bureau of Sanitation, Department of Public Works. When asked how, he said. “There’s nothing active right now. Basically they just say that we can’t accept controlled substances.”