Professional Service Industries wants to be the one you call when you need to get the lead out. The company, which is known as PSI, provides testing for lead-based paint and asbestos, among other services. One of the largest engineering and environmental consulting firms in North America, PSI also is one of the leading independent testing organizations. Its services include geotechnical engineering, soil and materials testing, and facilities and roof consulting. The company provides its testing and consulting services to companies involved in site selection, design, construction, and property management. Investment firm Olympus Partners owns a controlling stake in PSI.