Respondent operates enclosed, anaerobic biodigester systems that process food processing, biomass waste streams to produce a biogas intermediate that contains methane. This biogas is further processed (in an enclosed system) to produce a final compressed natural gas that is sold as a transportation fuel. Gaseous hydrogen sulfide has on occasion been released in small concentrations when sulfur-containing waste streams mixed with non-compliant acidic wastewaters. As a result, Respondent produces, processes, handles or stores biogas, methane, and hydrogen sulfide at the Facility. On or about December 14, 2016, at 19:03, an employee drilled a hole into an anaerobic digester, which was producing, processing, handling, and/or storing biogas, methane, and/or hydrogen sulfide, to install a pipe. When the employee’s drilling pierced the anaerobic digester, biogas, methane, and/or hydrogen sulfide were released. The employee was injured as a result of the release and transported to a local hospital for medical treatment.