Storage tanks used in oil or natural gas production are subject to EPA’s 2012 New Source Performance Standards (NSPS) for VOCs if they have the potential to emit 6 or more tons of VOCs a year. On March 28, 2013, EPA proposed updates to its 2012 VOC performance standards for storage tanks used in crude oil and natural gas production to facilitate compliance with the standards and clarify requirements. The proposed changes reflect recent information showing that more higher-volume storage tanks will be coming on line than the agency originally estimated.

The updates adjust requirements for tanks built before March 28, 2013 and establish alternative emission limits for tanks where emissions have dropped. The prosed rule also clarifies test protocols for control equipment, clarifies the types of tanks subject to the rule, streamlines compliance monitoring requirements while EPA addresses monitoring issues raised in reconsideration petitions. Finally, proposal updates requirements for submitting annual reports. EPA anticipates taking final action on the proposed rule by July 31, 2013.

After its 2012 final standards were issued, EPA received supplemental information that led the agency to revise its estimate of storage tanks that would be subject to the rule. Based on that information, EPA now believes there will not be sufficient control equipment available for tanks to meet an Oct. 15, 2013 deadline for storage tanks to control VOC emissions by 95%. In light of that information, EPA is proposing to address storage tanks in two groups in order to focus the limited control equipment currently available on the tanks likely to have the highest emissions.

o Group 1 tanks: Emissions from tanks generally decline over time, because the amount of liquid that moves through the tank declines as production from a well slows. For tanks constructed between Aug. 23, 2011 and March 28, 2013, EPA is proposing a two-part requirement:

  • Tank owners/operators would have until Oct. 15, 2013 to report that the tank is on line and provide the tank’s geographic coordinates.
  •  If there is a change that potentially would increase the tank’s emissions– such as the addition of a well supplying the tank or the refracture of an existing well — the owner/operator would have to install controls to reduce VOC emissions by 95% within 60 days of the change or by April 15, 2014, whichever is later.

o Group 2 tanks: Tanks that come online after March 28, 2013 would have to have controls to reduce VOC emissions by 95% in place by April 15, 2014 or within 60 days after startup, whichever is later.

EPA also is proposing an alternative emissions limit for storage tanks that would allow owners/operators to either:

1) Reduce VOC emissions at a tank by 95%, as required in the original rule; or

2) Demonstrate emissions from a tank have dropped to less than 4 tons per year of VOCs without emission controls.

This alternative limit would reflect the decline in emissions that occurs at most tanks over time and allow owners/operators to shift control equipment to higher-emitting tanks. To qualify for this emissions limit, owners/operators would have to document that emissions had been below 4 tons for at least 12 consecutive months. If emissions increase (at or above the 4 ton-per-year limit), owners/operators would have 30 days to meet the 95 % reduction requirement.

The 2012 NSPS allows owners/operators to use manufacturer-tested emission control device models (combustors) that have been demonstrated to reduce VOC emissions from storage tanks by 95 %, rather than requiring field performance testing of these devices. The proposed amendment  aligns the protocol that emission control manufacturers must use in testing the controls with the testing protocol required in EPA’s 2012 air toxics regulations for storage tanks. EPA also is proposing to allow tank owners/operators to use control devices that are designed to reduce VOC emissions by 95 %, while the agency reviews issues raised in the reconsideration petitions related to field testing protocol requirements. EPA expects to address this issue by the end of 2014.

The 2012 final NSPS required that tank owners/operators conduct a performance test and use a continuous parametric monitoring system (CPMS) to demonstrate that they are meeting requirements to reduce VOC emissions from tanks by 95%. Several reconsideration petitions have said this requirement is overly strict, based on the large number of storage tanks affected each year, and the remoteness of many of the well sites where the tanks are located. EPA is continuing to evaluate this issue and will address it by the end of 2014.

EPA is proposing to streamline compliance and monitoring requirements for tanks that have already installed VOC controls while the agency completes its evaluation of the monitoring issue. For tanks with controls, the proposal would require monthly inspections of covers, closed-vent systems and control devices. This step is expected to minimize VOC emissions by leading to prompt repairs, while requiring little or no specialized monitoring training or equipment. Records of these inspections, which can be conducted by personnel visiting the tank site for other work, must be kept on site.

The proposed rule also clarifies the type of storage tank that is subject to the NSPS. Tanks that are considered “affected sources” would have VOC emissions of 6 or more tons per year and are used to store crude oil, condensate, unrefined petroleum liquids known as “intermediate hydrocarbon liquids,” and produced water. Fuel tanks, for example, are not covered by these rules. Storage tanks subject to the rule may be located anywhere along the oil and natural gas production process from the natural gas well to the point where gas enters the distribution system to the point where oil is transferred to the pipeline for crude oil production. Storage tanks located at refineries are not covered by this rule.

The 2012 final NSPS required that owners/operators submit an annual report on well completions, along with information on storage tanks and other equipment constructed or modified during the year. The rule gave owners/operators 30 days to submit the report, which must be certified by a senior company official. Several of the reconsideration petitions noted that 30 days is not enough time to compile the required information and have the report signed by the senior official. EPA is proposing to give owners/operators 90 days to submit this report.


%d bloggers like this: