The U.S. Geological Survey (USGS) is conducting a market survey to identify firms capable of providing passive gas samplers and analytical services for volatile organic compounds (VOCs) in sanitary sewers. The initiative aims to support the U.S. Environmental Protection Agency (EPA) in investigating trichloroethene (TCE) contamination, requiring samplers that are suitable for high-humidity sewer environments, easy to deploy, and capable of selectively absorbing target VOCs while excluding other sewer gases. Interested contractors must analyze six specific VOCs to precise detection limits using EPA method TO-17 and deliver results within 40 days, including a tabular summary and a Level IV data package. Responses are sought from various small business categories under NAICS code 541380, with submissions due by December 31, 2025, at 5:00 PM MST to KKeuma@usgs.gov. This is a Sources Sought Notice and not a solicitation.