EPA is making the changes based on information received after the 2012 standards were issued that shows more storage tanks will come online than the agency originally estimated.

Storage tanks that emit 6 or more tons of VOCs a year must reduce emissions by 95%. The rule establishes two emission control deadlines:

• tanks that come online after 12 April 2013 are likely to have higher emissions and must control VOCs emissions within 60 days or by 15 April 2014, whichever is later; and

• tanks that came online before 12 April 2013 are likely to have lower emissions and must control VOC emissions by 15 April 2015.

The updated standards also establish an alternative emissions limit that would allow owners/operators to remove controls from tanks if they can demonstrate that the tanks emit less than 4 tons per year of VOC emissions without controls. In addition, the rule streamlines compliance and monitoring requirements for tanks that have already installed controls.

The oil and natural gas industry uses tanks for temporary storage of crude oil, condensate and other liquids, before those liquids are moved to a pipeline, sold or moved for disposal. These storage tanks can be sources of emissions of ozone-forming VOCs, along with several toxic air pollutants, including benzene. The new final action does not affect the April 2012 standards for capturing natural gas from hydraulically fractured wells.

The updates were in response to petitions from several industry and environmental organizations, and the Texas Commission on Environmental Quality for reconsideration of the 2012 New Source Performance Standards for Oil and Natural Gas Production. (EPA is continuing to evaluate other issues raised in those petitions.) Those standards rely on proven technologies and best practices to reduce emissions of ozone-forming VOCs and air toxics, including benzene and hexane.

Exposure to ozone is linked a variety of health effects, including aggravated asthma, reduced lung function and increased susceptibility to respiratory infections, in addition to increased risk of premature death from heart or lung disease. Benzene and hexane are air toxics, which can cause cancer and other serious health effects.