The U.S. Environmental Protection Agency has concluded that Tonawanda Coke Corp. is a “very significant source of benzene,” a chemical classified as a hazardous air pollutant (HAP) under the federal Clean Air Act. Tonawanda Coke is a merchant producer of metallurgical coke for ferrous foundries and steelmakers, and other industrial consumers. In April, EPA ordered Tonawanda Coke to find and correct deficiencies in its environmental management systems, and to explain the causes of coke-oven gas releases at its Western New York plant. EPA states that exposure to benzene and other HAPs can significantly harm human health, and excessive exposure to benzene is a known cause of cancer. Test readings were taken by a Tonawanda Coke contractor at the plant site in May, and represent a snapshot of the process on the days they were taken. Tonawanda Coke submitted its report on the tests in September. The differential absorption light detection and ranging (DIAL) test is a laser-based optical technique that measures the concentration of gases in the air, including benzene. The CAA defines a major source of hazardous air pollutants as one that emits more than 10 tons per year of a single air toxic, or more than 25 tons per year of a combination of air toxics. “Based on the DIAL test, Tonawanda Coke's estimated annual benzene emission rate for regulatory compliance purposes is 90.8 tons per year. The DIAL test also indicated that the actual benzene emissions at TCC vary over time based on production activity at the plant and a variety of other factors,” according to the EPA’s report issued this week. EPA concludes that most of the benzene at the plant site is traceable to the process area, not the smoke stack. EPA describes these as “fugitive” emissions. “These test results show that the Tonawanda facility is a very significant source of benzene,” stated EPA Regional Administrator Judith Enck. EPA and the New York State Department of Environmental Conservation (NYSDEC) will to determine what actions need to be taken to reduce the benzene emissions.