The two companies will also pay a combined $3.3m civil penalty to the US as well as to Alabama and Louisiana, and $200,000 to Louisiana organizations for environmental education and emergency operations.

Under the settlements, Shell Chemical will apply new air pollution control technologies and implement other measures to reduce emissions from some of the largest emitting units at its petroleum refining facilities in Saraland, Alabama and St Rose, Louisiana.

Cynthia Giles, assistant administrator of EPA’s office of enforcement and compliance assurance, said: “These settlements demonstrate EPA’s continuing commitment to increase compliance and reduce emissions from this industrial sector. As a result of today’s actions, the communities living nearby these refineries can look forward to cleaner, healthier air.”

Shell Chemical Yabucoa operates a facility in Yabucoa, Puerto Rico. For independent business reasons, the company decided to shut down its refining operations at the facility in Puerto Rico in the summer of 2009. The company still continues to operate the existing gasoline terminal there. Collectively the three facilities had a combined production capacity of approximately 235,000 barrels per day.

In addition, the two refineries in Alabama and Louisiana and the terminal operations in Puerto Rico will upgrade their leak-detection and repair practices to reduce harmful emissions from pumps and valves, implement programs to minimize the number and severity of flaring events, and adopt new strategies for ensuring continued compliance with benzene waste requirements under the clean air act.

Together, both settlements will reduce air emissions of sulfur dioxide (SO2), nitrogen oxides (NOx) and other harmful pollutants by approximately 1,450 tons per year.

The annual emission reductions from all three refineries, including the emissions associated with the shutdown at Yabucoa, are estimated to be approximately 645 tons of SO2 and approximately 813 tons of NOx, as well as additional reductions of volatile organic compounds and benzene.