Sites of former meth labs are known for their toxicity, but the risk doesn’t end with labs. The Oregon Health Authority says that homes once occupied by heavy meth users can be contaminated, too, and must be cleaned carefully.

Brett Sherry, program manager for healthy homes and schools at OHA, works to clean up illegal drug manufacturing sites, but he says residues could be present where people have simply used meth. “Primarily with the use piece, somebody is smoking methamphetamine, it volatilizes, it goes up into the air and it kind of settles out and sticks to surfaces,” he says.

Oregon’s standard of clean up is very conservative when it comes to drug labs, Sherry says, because of the worst-case scenario of a child crawling on the floor and putting its hands in its mouth. “That hand-to-mouth behavior can pick up a lot of meth residues and that child could ingest enough of that methamphetamine to have a dose of meth,” he says.

Sherry says that people who suspect their dwellings are contaminated with meth could hire a cleanup service to test for it, which he recommends, or purchase home test kits, either the “yes-no” pregnancy-test style or one in which samples are sent in for analysis.

When companies decontaminate a home, Sherry says they use a methodical procedure in which they repeatedly wash and rinse the ceiling, then the walls, then the floors, backing out to avoid cross-contamination.

A list of contractors licensed to clean up drug labs in Oregon is available at wkly.ws/1mk. There is no licensing requirement for sites of meth use.