Remediation services includes oil or chemical spill clean up, restoration of contaminated sites, and hazardous waste management. Common projects include oil collection, asbestos removal, spill vacuuming, brown field rehabilitation, soil recovery and river dredging. Facility remediation services clean up contaminated sites, buildings, and other operating facilities along with soil and groundwater.  Groundwater contamination comes from both point sources and non-point sources. Point sources include landfills, petroleum storage tanks, and accidental spills. Non-point sources include farmland treated with pesticides and fertilizers. A contaminated aquifer may be unsafe for many years. Remediation services can use technology in innovative ways to remediate groundwater contamination. For example, electrical resistance heating (ERH) brings subsurface moisture to a boil. The steam and vapors carry contaminants to the surface for treatment.