ATC Group Services LLC (ATC) is a full-service environmental consulting and industrial hygiene firm operating more than 115 offices nationwide. Over the past 35 years, ATC has become one of the leading national providers of environmental and engineering support services nationwide. We are a full service firm specializing in Environmental Consulting, Industrial Hygiene, Geotechnical Engineering, Construction Materials Testing & Special Inspection, Petroleum, Due Diligence, and Environmental Health & Safety Training.