Brownfield Subslab provides professional engineering consultation related to soil vapor control at development sites.

Brownfield Subslab provides engineering design and shop drawings for construction of soil vapor mitigation systems. System designs may include passive soil gas venting and barrier membranes; and/or active elements such as gas detectors, alarms, telemetering, fans and other devices.
Projects Completed/Ongoing
  • High School - City of Los Angeles
  • Refinery - City of Torrance
  • Supermarket - City of Los Angeles
  • Vent Cones Supply and Installation - City of Los Angeles
  • Apartment Buildings - City of Los Angeles
  • Tenant Improvements - City of Los Angeles
  • Monitoring/Installation of Wells - City of LA
  • Senior Housing - Los Angeles County

Brownfield Subslab provides testing services and evaluation of test reports done by others for soil vapor conditions at development sites. Approved contractor to provide methane gas services in city of Los Angeles, CA.

Brownfield provides deputy-type special inspection and certification of soil gas mitigation systems, with particular emphasis on membrane quality assurance/quality control.

Mr. John Sepich has extensive expert witness experience related to soil vapor and soil gas issues. Brownfield Subslab also provides forensic research and forensic engineering services.

John Sepich holds four patents related to soil vapor control.