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EPA publishes Billings/Laurel air quality plan

Release Date: 04/21/2008
Contact Information: Cynthia Cody, 303-312-6228,

(Denver, Colo. -- Apr. 21, 2008) EPA today announced publication of a Federal Implementation Plan (FIP) for the Billings/Laurel Air Quality Area to keep air quality within the health limits for sulfur dioxide (SO2). This FIP supplements those portions of the State Implementation Plan (SIP) rejected by EPA in 2002 and 2003.

    The federal plan, in combination with the state SIP, shows how Billings and Laurel will meet national clean air standards for sulfur dioxide. The FIP and SIP restrict industrial facilities, like chemical manufacturing facilities, refineries and power plants that emit SO2.

    EPA’s plan sets limitations on four industrial facilities in the Billings/Laurel area: CHS Inc., ConocoPhillips, ExxonMobil and Montana Sulphur and Chemical Company (MSCC).

    Sulfur dioxide in the air is an irritant that may cause temporary breathing difficulty for people with asthma who are active outdoors. Longer-term exposures to high levels of sulfur dioxide gas and particles can cause respiratory illness and aggravate existing heart disease.

    In 2002 and 2003, EPA approved much of the state’s plan to control or reduce SO2 emissions from seven industrial facilities in the area, but parts of the state’s plan were disapproved. The FIP covers the disapproved parts of the state plan.

    EPA proposed the FIP on July 12, 2006, and held a public hearing in Billings on August 10, 2006. Public comments received on the proposed FIP have been addressed and some changes have been made in the final FIP in response to the comments.

    The FIP:
      -- restricts refinery flare emissions at all four sources and establishes methods for measuring emissions from the flares
      -- restricts the burning of certain gases at CHS, Inc.
      -- establishes methods for measuring emissions from various units at ExxonMobil
      -- clarifies that a stack and a flare at Jupiter Sulfur share an emission limit
      -- restricts emissions from MSCC’s SRU 100-meter stack
      -- restricts emissions at MSCC’s auxiliary vent stacks and SRU 30-meter stack and establishes methods for measuring emissions from these units

    The record of EPA's action may be found at:
    by searching for Docket ID No. EPA-R08-OAR-2006-0098.