Contractors’ and home renovators’ favorite supermarketHome Depot is under investigationthis week by the federal government for allegedly selling Chinese goods to government customers.

Federal law mandates that only U.S. materials can be used in public construction projects.

Earlier in June, the South Coast Air Quality Management District (AQMD) filed suit against Home Depot alleging that the company’s stores displayed and sold coatings and paints containing high levels of volatile organic compounds (VOCs). The AQMD inspectors found illegal products at more than two dozen stores.

Products were found at the Home Depot stores even after Home Depot management was notified of the problem, according to AQMD. In fact, the agency says, in some cases the suspect product was marked down for quick sale.

Paints and coatings are a major source of air pollution, responsible for 23 tons per day of VOC emissions in Southern California. That’s an amount greater than the VOCs emitted by 1.5 million cars.

AQMD is the air pollution control agency for Orange County, Calif., and for major portions of Los Angeles, San Bernardino and Riverside counties.