O'Brien, Claudia M.

Claudia M. O'Brien

Retired Partner

Claudia O’Brien retired from the partnership in June 2021. She is former Co-Chair of the firm’s Environmental Regulation & Transactions Practice, Chair of the Air Quality & Climate Change Practice, and Vice Chair of the Finance Committee. She has represented clients in agency petitions, rulemaking proceedings and litigation, as well as on compliance and enforcement, in a full range of federal environmental statutes. Ms. O’Brien has particular experience in all aspects of the Clean Air Act and the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), as well as the Clean Water Act, the Resource Conservation and Recovery Act (RCRA), and the Endangered Species Act (ESA). She also advised on regulations impacting genetically engineered plants. She possesses specific technical and business knowledge of power plants (both fossil-fueled and biomass-fueled) and the pesticide industry, as well as extensive experience in toxicology and risk assessment.

Ms. O’Brien joined the firm in 1994 after six years at the Environmental Protection Agency (EPA), where she worked on issues involving water, air, and toxic substances. While working full-time at EPA, Ms. O’Brien attended law school at the Georgetown University Law Center.

Ms. O’Brien was a member of the Utility MACT Working Group, a subcommittee of the Clean Air Act Advisory Committee and is currently Vice Chair of the ABA’s Committee on Pesticides, Chemicals, and Community Right-to-Know. She is a co-author of “Walking the Line Between the Clean Air Act and the Federal Power Act: Balancing Emission Reductions and Bulk Power Reliability,” published in The Electricity Journal.

Ms. O’Brien was consistently ranked by Chambers USA in its District of Columbia, Environment category since 2012. In 2021, she was included on Lawdragon 500’s Leading US Environmental & Energy Lawyers. Ms. O'Brien has also been named by Benchmark Litigation as a Litigation Star in the District of Columbia and recognized as one of the Top 250 Women in Litigation in the US from 2012-2016. She is listed in the International Who’s Who of Environmental Lawyers 2012-2020 for her “‘sector-leading expertise’ in relation to all aspects of the Clean Air Act and Clean Water Act.” Ms. O’Brien has also been included in the 2014-2017 and 2020 Expert Guides’ Women in Business Law for Environment – United States.

At the time of her retirement, Ms. O’Brien had been admitted to the Third, Fourth, Sixth, Seventh, Ninth, Tenth, and D.C. Circuits, as well as the US Supreme Court.  

Thought Leadership

Ms. O’Brien was a frequent author and contributor to Latham subject matter publications, including numerous client alerts and webcasts. In addition, publications include: 

  • "President Trump Takes First Step on Long Road to Roll Back Climate Rules," Client Alert (April 2017)
  • “Reducing Ozone Regulation Costs Under the New Administration,” Client Alert (March 2017)
  • “US Environmental Regulations to Face Rollbacks, but Reform Likely to be Tempered by Legal Barriers,” Latham.London (March 2017)
  • “President Signs Executive Order Directing EPA and Army to Review and “Rescind or Revise” Clean Water Rule,” Latham’s Clean Energy Law Report (March 2017)
  • “Re-Evaluating The Clean Water Rule: A Long Road Ahead,” Law360 (March 2017)        
  • “EPA Targets Oil and Gas Sector with Suite of New Emissions Rules,” Latham's Clean Energy Law Report, (May 2016)
  • “Proposed Rule from U.S. Department of the Interior Increases Pressure on Coal Mining Industry,” Client Alert (November 2015)
  • “EPA Proposes New Methane and VOC Emissions Limits,” Client Alert (October 2015)
  • “EPA Expands Air Quality and Climate Change Regulations,” Client Alert (October 2015)
  • “EPA Finalizes Historic Greenhouse Gas Emission Reduction Program,” Client Alert (August 2015)
  • “Proposed Rule from US Department of the Interior Increases Pressure on Coal Mining Industry,” Latham's Clean Energy Law Report, (July 2015)    
  • “The Supreme Court Strikes Down the Mercury and Air Toxics Standards,” Client Alert (July 2015)
  • “EPA’s Fiscal Year 2014 Civil Enforcement Results Reveal Agency’s Shifting Focus,” Client Alert (February 2015)
  • “CARB Invalidates Offsets for Facility’s Alleged RCRA Noncompliance,” Latham's Clean Energy Law Report, (November 2014)
  • “EPA Proposes Unprecedented Greenhouse Gas Emission Reduction Program,” Client Alert (June 2014) 
  • “The Supreme Court Upholds EPA’s Cross-State Air Pollution Rule,” Client Alert (May 2014)
  • “EPA’s Proposed Rule for New Power Plants Could Trigger Excessive Title V Permit Fees,” Client Alert (April 2014)
  • “States Voice Strong Opposition to EPA Clean Air Act Rule,” Client Alert (June 2013)
  • “EPA Proposes New Effluent Limitation Guidelines for Power Plants,” Law 360 (May 2013) 
  • “Implementing Carbon Taxes: Considerations, Realities, and Lessons Learned,” BNA (May 2013) 
  • “Using Disjointed Global and Domestic Climate Change Policies to the Client’s Advantage,” The Legal Impact of Climate Change (April 2013) 
  • “Outlining the Attempts to Invalidate California’s First GHG Auction,” (November 2012) 
  • “Getting the Deal Through – Climate Regulation 2013: United States,” (November 2012) 
  • “Walking the Line Between the Clean Air Act and the Federal Power Act: Balancing Emission Reductions and Bulk Power Reliability,” The Electricity Journal (January/February 2012) 
  • “Principles Promoting,” Project Finance (November 2011)


  • JD, Georgetown University Law Center, 1994
  • BA, Yale University, 1987