United States Environmental Protection       Office of Water          EPA-821-F-06-007
            %     Agency                            4303T                June 2006

      ,^^_  /   ui
1 ^Mgf  j   COOLING WATER INTAKE STRUCTURES - SECTION 316(b)
 %^^^e*°    Final Rule for Cooling Water Intake Structures
    ^i PRO**-       at phase III Facilities
  EPA is publishing the third and final part of regulations designed to minimize harmful
  impacts on aquatic life caused by cooling water intake structures. This "Phase III" rule
  establishes categorical requirements under section 316(b) of the Clean Water Act for new
  offshore oil and gas extraction facilities that have a design intake flow threshold of greater
  than 2 million gallons per day (MGD) and that withdraw at least 25 percent of the water
  exclusively for cooling purposes.

  EPA decided that uniform national standards are not the most effective way at this time to
  address cooling water intake structures at existing facilities that were not covered under the
  earlier Phase II rule. Instead, we will continue to rely upon the existing National Pollutant
  Discharge Elimination System (NPDES) program, which implements section 316(b) for
  these facilities on a case-by-case, best professional judgment basis. This rule does not change
  the regulatory requirements for facilities subject to the Phase I or Phase II regulations.
  Background

  Section 316(b) of the Clean Water Act requires NPDES permits to ensure that the location,
  design, construction, and capacity of cooling water intake structures reflect the best
  technology available to minimize adverse environmental impact. Such impacts include death
  or injury to aquatic organisms by impingement (being pinned against screens or other parts of
  a cooling water intake structure) or entrainment (being drawn into cooling water systems and
  subjected to thermal, physical or chemical stresses).

  Rulemaking in Three Phases

  EPA divided this rulemaking into three phases. Phase I for new facilities was published in
  December 2001. Phase II, for existing electric generating plants that use at least 50 MGD of
  cooling water, was published in July 2004. Phase III addresses other existing facilities, as well
  as new offshore and coastal oil and gas extraction facilities that are designed to withdraw at
  least two MGD.  Any facility not covered by these national categorical rules will continue to
  be subject to 316(b) requirements set by the NPDES Permitting Director on a case-by-case,
  best professional judgment basis.

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Today's Final Phase III Action

EPA has decided to establish categorical regulations for new offshore oil and gas extraction
facilities that have a design intake flow threshold of greater than 2 MOD and that withdraw at
least 25 percent of the water exclusively for cooling purposes.  Based on available data,
analyses, and comments, the Agency decided not to promulgate a national categorical rule
for Phase III existing facilities. In light of the ratio of the costs of any of the three proposed
regulatory options to their benefits, the best approach for existing facilities is through
conditions established by NPDES permit directors on a case-by-case basis using best
professional judgment.
How to Get Additional Information

For more information, please call Paul Shriner at 202-566-1076 or send an email to
shriner.paul@epa.gov.  You can also learn more about this rule by visiting EPA's Internet
web site at http://www.epa.gov/waterscience/316b.

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