Federal authorities have opened a criminal investigation of Chevron after discovering that the company detoured pollutants around monitoring equipment at its Richmond refinery for four years and burned them off into the atmosphere, in possible violation of a federal court order, The Chronicle has learned. The U.S. Environmental Protection Agency’s criminal enforcement unit opened an investigation in early 2012, more than two years after the local inspectors made their discovery, according to air-quality officials and others familiar with the probe. Chevron says its use was inadvertent and that it estimates that the amount of released sulfur dioxide – one of the major components of flaring gas pollution – was minimal. The criminal probe came to light after The Chronicle obtained citation data from the air-quality district under a state Public Records Act request, following the Aug. 6 fire that destroyed part of the Richmond refinery. Health risksThe federal investigation centers on Chevron’s burning, or flaring, of gases created during the superheating needed to generate fuels from crude oil. Under a 2005 settlement of a lawsuit filed against it by the Environmental Protection Agency, claiming that Chevron violated federal environmental rules, the company agreed to limit flaring at Richmond and its other refineries and account for each flaring event. The Bay Area air-quality district, which enforces federal air standards, ordered Chevron to install monitors at the Richmond refinery to measure pollutants in the gases burned off during flaring, and to report all instances of flaring. Spotted by inspectorsWayne Kino, an enforcement manager for the air-quality district, said two inspectors with the agency became suspicious Aug. 17, 2009, when they saw steam from a flare coming from a high-pressure, high-temperature hydrocracking complex in Richmond called the Isomax unit, where 62,000 barrels of oil a day are converted into gasoline and jet fuel.   Original post on sfgate.com →   Comments on reddit.com →