Established in 1927 as Toledo Testing Laboratory, TTL Associates is a full-service environmental, testing and geotechnical engineering firm. It also offers drilling and probing services, and maintains a presence in Toledo, Ohio. The firm employs certified industrial hygienists, professional registered engineers, geologists, environmental microbiologists, certified roof inspectors, drilling experts, and safety and health trainers. TTL Associates serves various banks, gas stations, convention centers, manufacturing facilities, schools, and county, state and federal agencies. Its in-house analytical laboratory is a part of the National Voluntary Laboratory Accreditation program administered by the National Institute of Standards and Technology. The firm is also affiliated with the American Water Works Association, the Canadian Society of Civil Engineers and the Ohio Association of Consulting Engineers.