GeoTek provides geotechnical, construction materials, and environmental services in South Dakota, Iowa, Minnesota, North Dakota, and Nebraska. These services include Phase I and II Environmental Site Assessments, Targeted Brownfield Assessments, transaction screens, asbestos and lead paint assessments, mold and indoor air quality testing, contamination assessments, documentation of the removal of underground storage tanks, groundwater studies of contaminated sites, design of soil and groundwater remediation systems, remedial system installation, and operation and maintenance. GeoTek also provides a number of other services to address concerns in the area of landfills, storm water, air quality, industrial pre-treatment, water supply, and industrial hygiene. GeoTek is a privately owned company, actively managed by its principal with one office located in Sioux Falls, South Dakota. GeoTek was incorporated in 1988. Ralph Lindner is the Owner and President of GeoTek Engineering & Testing Services, Inc.