Under a final rule issued October 15, 2003 (68 FR 59328), smaller storage vessels and process tanks have been exempted from the EPA’s new source performance standards (NSPS) for volatile organic liquid storage vessels.  The final rule amendments exempt certain storage vessels by capacity and vapor pressure, exempt process tanks, and add a definition for “process tank”

This eliminates recordkeeping requirements for storage vessels with a capacity less than 75 m³ (19,813 gallons), for storage vessels with a capacity between 75 and 151 m³ (39,890 gallons) storing liquid with vapor pressure less than 15 kPa (2.18 psia), and for storage vessels with a capacity equal to or greater than 151 m³ storing liquid with vapor pressure less than 3.5 kPa (0.51 psia).

The rule defines “process tank” as follows:  a tank that is used within a process (including a solvent or raw material recovery process) to collect material discharged from a feedstock storage vessel or equipment within the process before the material is transferred to other equipment within the process, to a product or by-product storage vessel, or to a vessel used to store recovered solvent or raw material.

It also exempts process tanks, as well as storage vessels subject to the National Emission Standards for Hazardous Air Pollutants (NESHAP) for vegetable oil production (40 CFR Part 63, Subpart GGGG).

The exemption represents a reversal of EPA's March 27, 2000, memorandum that classified process tanks as storage vessels subject to the “Standards of Performance for Volatile Organic Liquid Storage Vessels (Including Petroleum Liquid Storage Vessels) for Which Construction, Reconstruction, or Modification Commenced After July 23, 1984” (40 CFR Part 60, Subpart Kb).  This final rule is a result of a settlement agreement between EPA and the American Forest & Paper Association.

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