Beveridge & Diamond

EPA To Review Climate Change Impacts on Ocean Acidification under Clean Water Act

Beveridge & Diamond, P.C., April 20, 2009

On April 15, 2009, EPA published a notice of data availability (“NODA”), initiating a process for evaluating information on ocean acidification and reconsidering the current marine water quality criterion for pH, which was first established in the 1970s.  74 Fed. Reg. 17,484 (April 15, 2009) (click here to view the NODA).  The move comes in response to a 2007 petition by the Center for Biological Diversity (“CBD”) that asked EPA to consider the effects of ocean acidification, understood generally as a decrease in the pH of ocean waters attributed by CBD and others to the impacts of increasing greenhouse gas emissions, on marine aquatic life.  The petition represented a novel legal theory that EPA, under the Clean Water Act (“CWA”), could address climate change based on water quality impacts.  CBD filed similar water quality-based petitions in each coastal state, seeking complementary actions under the CWA.  EPA’s decision to evaluate information on ocean acidification for possible regulatory measures under the water quality authorities of the CWA represents a new chapter in the climate change debate.  

Legal Background

Section 304(a) of the Clean Water Act requires EPA to publish and, from time to time, revise, water quality criteria (“criteria”) that accurately reflect the “latest scientific knowledge” on the kind and extent of “all identifiable effects” on aquatic life and human health that might be expected from the presence of pollutants in any body of water.  33 U.S.C. § 1314(a).   The criteria are most often expressed as numeric limits on the amount of a pollutant that can be present without causing harm to aquatic life or human health.  Criteria are to be based on available data and scientific determinations of the relationship between pollutant concentrations and its effects on human health and the environment.  When developing criteria, EPA does not consider social and economic impacts, or the technological feasibility of meeting the pollutant concentration values.  74 Fed. Reg. at 17,486.

Section 304 criteria set by EPA are non-regulatory, scientific assessments of ecological effects.  As such, criteria serve only as recommended guidance to assist States and Tribes in fulfilling their responsibilities under the CWA to establish water quality standards (“standards”) for the protection of designated uses (i.e. drinking water, fishing, swimming, navigation, etc.).  See 33 U.S.C. § 1313.  EPA’s national criteria are recommended limits that, if met, should protect aquatic life or human health.  In promulgating standards, States and Tribes may 1) adopt EPA criteria, 2) modify EPA criteria to suit site-specific conditions, or 3) base standards on “other scientifically defensible methods.”  40 C.F.R. § 131.11(b).  If approved by EPA, the standards set by States and Tribes become enforceable maximum acceptable pollutant concentrations in ambient waters.

CBD’s petition to EPA to revise the pH criteria attempts to set in motion, longer-term,  the water quality standard-setting process by States and Tribes that will ultimately result in Total Maximum Daily Loads for pH in affected ocean waters, which, in turn, could drive CWA-based controls of greenhouse gases emissions causing ocean acidification.

Ocean Acidification and the pH Criterion for Marine Aquatic Life

Oceans absorb an estimated one third of the anthropogenic CO2 emitted into the atmosphere.  As CO2 dissolves into ocean waters, the water becomes more acidic, causing a reduction in pH.  The primary threat to marine life posed by decreases in the pH of ocean waters is the inhibited ability of marine animals to build and maintain necessary skeletons and shells.  Various marine species, including coral, are seen as at risk from the changes in ocean pH attributed in recent years to rising CO2 emissions world-wide. 

EPA’s current criterion for marine pH, which applies to open-ocean waters within three miles from state coastlines, was established in 1976 at a recommended range of 6.5 to 8.5 for the protection of marine aquatic life.  In December 2007, the Center for Biological Diversity petitioned EPA to revise its recommended national marine pH water quality criterion for the protection of aquatic life to account for risks posed by acidification.  As noted, CBD also petitioned every coastal state to list their ocean waters as impaired under the CWA for pH, an action that, if taken, would lead to a TMDL process for pH in every such listed water.  EPA’s April 15 NODA asserts the Agency’s intent to respond to CBD’s federal petition by gathering and evaluating information necessary to consider revisions to the criterion. 

Under the April 15 notice, EPA is currently soliciting information that will help it determine whether a revision is necessary to protect the marine uses designated by States and Tribes.  Comments must be submitted to EPA by June 15, 2009.  EPA expects to make a final decision regarding whether to revise the criterion within one year.  If revisions are deemed necessary, a new round of public comment will ensue. 


States and EPA were active in the development of water quality standards for conventional pollutants, including pH, during the 1970s when the CWA’s water quality requirements were new.  Attention quickly turned to the CWA’s technology based controls for point sources, with less focus on the water quality-based programs.  Lawsuits over the status of the TMDL program during the 1990s drove EPA, States and Tribes to reinvigorate their approaches to water quality based improvements under the CWA.  As a result, in recent years, EPA has recognized a general need to revisit water quality criteria for certain pollutants.  While EPA’s reconsideration of the pH criterion for protecting marine aquatic life is consistent with the renewed attention to the water quality authorities, the notion that water quality criteria might be used to address a phenomenon associated with greenhouse gas emissions, typically seen as the province of the Clean Air Act, represents a novel application of EPA’s CWA authority. 

Climate change advocacy in recent years has invoked several other environmental laws such as the Clean Air Act, the Endangered Species Act, and the National Environmental Policy Act to address issues associated with climate change.  Until EPA’s April 15 NODA, federal agencies have generally opposed such efforts by environmental advocates to employ the Clean Water Act as a new mechanism to address climate change.  For example, the Army Corps of Engineers is currently defending in court its decision not to consider the climate impacts of a coal-to-liquids fuel plant during the “public interest review” process of issuing a wetlands permit.  See Natural Resources Defense Council v. Army Corps of Engineers, No. 09-00588 (N.D. Ohio filed Jan. 14, 2009); 33 U.S.C. § 1344; 33 C.F.R. § 320.4(a)(1).  Furthermore, EPA is currently in settlement negotiations over a lawsuit brought by environmental advocates that sought to force EPA to consider climate change impacts during the approval process for certain Total Maximum Daily Loads.  See Conservation Law Foundation v. EPA, No. 08-238 (D. Vt. filed Oct. 28, 2008); 33 U.S.C. § 1303.

EPA’s response to CBD’s ocean acidification petition, on the other hand, signals that the Obama administration may be willing to consider non-traditional uses of existing legal authorities to address climate change.  This shift in direction raises new questions about the inherent limitations of the Clean Water Act to address a problem caused primarily by air emissions.  Although EPA, the States and Tribes have used TMDLs to address certain pollutants located in water bodies due to air deposition (e.g., mercury, nutrients), the effectiveness of this approach to reduce air-emitted pollutants to water bodies has not been demonstrated. 

Whether or not possible revisions to the marine pH criterion could effectively impact the sources releasing CO2 into the atmosphere, EPA’s call for scientific information and data looks to advance the Agency’s learning about ocean acidification and its potential negative effects on marine ecosystems.  Furthermore, stakeholders should expect mounting attention to climate change considerations under traditional environmental authorities, even where the relationships between the laws and the causes and effects of climate change are not readily apparent. 

For further information about the EPA’s action and possible implications, please contact Karen Hansen (, (202) 789-6056), Richard Davis (, (202) 789-6025), or Russ LaMotte (, (202) 789-6080).  This alert was prepared with the assistance of Graham St. Michel. 




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