Mary Mendoza


Mary Mendoza is a trusted advisor to companies in finding solutions to their environmental issues. Whether the issue is environmental compliance, site cleanup, environmental enforcement or toxic tort litigation, Mary helps clients successfully navigate the complex area of environmental law. Mary brings this practical knowledge of environmental law to corporate, real estate and other transactions, to assist clients in identifying environmental risks and manage those risks to a successful conclusion.

During her career, Mary has counseled clients from most every industry on environmental risks. Mary’s representations stretch from the oil patch to your local shopping center, and all types of businesses in between.

Mary earned her undergraduate degree in Civil Engineering from the University of Texas at Austin, where much of her course work focused on environmental issues. Mary uses the technical background to explain complex environmental issues in clear, concise terms for clients.

Mary’s experience includes many significant and high profile matters. For example, Mary recently assisted a private equity fund in the acquisition of five papers mills throughout the eastern US and Canada and also assisted a private equity fund in the purchase of a recycling facility out of bankruptcy, using the bankruptcy court to settle substantial Superfund and state environmental liabilities from historic operations. She regularly represents a major U.S. retailer on environmental issues associated with the acquisition and development of new store locations. In addition, Mary regularly appears before state and federal agencies on enforcement matters, including representing an oil and gas exploration and production company in a two week UIC permitting contested hearing and a manufacturer of consumer products in Clean Air Act enforcement action. She also represents clients on significant Superfund matters. Mary’s technical background is of particular value in addressing the complex technical issues for site remediation, such as her recent representation of a major retailer in the remediation of an urban site for the development of a new retail store.  

Mary frequently speaks and writes on environmental issues and is a co-author of the Thomson Reuters Texas Practice 2 –volume treatise on Texas Environmental Law.

Mary is a former chair of the Environmental and Natural Resources Law Section of the State Bar of Texas. Mary’s community involvement focuses on early childhood charities and education at the youngest levels, as shown by her involvement in Any Baby Can of Austin where she has previously served as the Chair of the Board of Directors.


Best Lawyers

Haynes and Boone Featured in Best Lawyers in America 2017

Best Lawyers in America, an annual referral guide listing outstanding lawyers throughout the U.S., has recognized 108 Haynes and Boone lawyers across more than 50 practice areas in the 2017 edition.

Published by Woodward/White, Inc., August 2017

Upcoming Event


Haynes and Boone Lawyers to Participate in Earth Day Legal Symposium

Haynes and Boone, LLP lawyers Jeff Civins, Diana Liebmann, Mary Mendoza, and Suzanne Murray will participate in a legal symposium to be held in connection with Earth Day Texas on April 20-21.


Haynes and Boone Advises Rmax Operating in Sale to Sika

A team of Haynes and Boone lawyers from three offices advised Rmax Operating, LLC, a market leader in building insulation technology for more than 37 years, in its agreement to be sold to Sika Corporation.

Professional Recognition

  • Selected for inclusion in Austin Business Journal's list of Who's Who in Energy, American City Business Journals, 2013
  • Recognized as a leading individual in Environmental Law (Texas) by Chamber's USA, Chambers & Partners, 2006, 2011-2016
  • Who's Who Legal, Law Business Research Ltd., Texas Environmental Law, 2007 and 2008
  • Texas Super Lawyers - Rising Stars Edition, Thomson Reuters, 2005-2007
  • The Best Lawyers in America, Woodward/White, Inc., Environmental Law, 2006, 2008-2017; Litigation - Environmental, 2012-2017

Selected Client Representations

  • Oil and gas exploration and production company in UIC permitting hearings.
  • National oil company in a multimedia environmental audit of refinery/chemical production facility.
  • Energy auditing firm in regulatory matters before Texas Real Estate Commission.
  • A major manufacturer in defending a CERCLA cost recovery action.
  • Major retailer in the environmental issues associated with the acquisition and development of store locations.
  • A private equity fund in the acquisition of environmentally impaired assets out of bankruptcy.
  • A major manufacturer in responding to a CERCLA information request.
  • Purchaser of contaminated property in negotiating a bona fide prospective purchaser agreement with EPA.
  • A manufacturer of water treatment equipment in a four week jury trial regarding alleged design defects.
  • A major corporation in a multi-million dollar remediation of a contaminated site under the state voluntary cleanup program.
  • Regulated industries in permit proceeding before the Texas Commission on Environmental Quality.
  • Defendants in enforcement hearings before the Texas Commission on Environmental Quality and the Environmental Protection Agency.
  • Defendant in enforcement action relating to alleged Clean Air Act violations arising out of release from commercial refrigeration system.
  • Defendants in negotiations of RCRA and CERCLA cleanup orders with the Environmental Protection Agency.
  • Multiple companies in the settlement of CERCLA liabilities with the Environmental Protection Agency.
  • A multi state corporation in multimedia compliance audits of plant operations.
  • Major property management companies in the defense of mold lawsuits and in the development of mold policies.
  • An alternative fuels plant in connection with permitting before the TCEQ.
  • A seller in a divestiture involving multi state property transfer notifications.
  • A corporation regarding compliance counseling and divestiture of a water and wastewater supply corporation.
  • Entities in appeals of agency orders.
  • Multiple defendants in toxic tort litigation regarding a commercial waste disposal facility.
  • Manufacturers in negotiations with the Consumer Product Safety Commission relating to product recalls.
  • Entities in a contested case hearing related to horse race track licensing before the Texas Racing Commission.

Selected Publications and Speeches

  • “Identifying and Indemnifying Against Environmental Risk,” Jeff Civins and Mary Mendoza, The University of Texas School of Law, 49th Annual William W. Gibson, Jr. Mortgage Lending Institute, Austin, Texas, September 17 and November 6, 2015.
  • “Toe the Line – Environmental Ethics,” 27th Annual Texas Environmental Superconference, Austin, Texas, August 5, 2015.
  • “Ethical Issues in Environmental Law: It's Not Easy Being Green,” with J. Civins, 5th Annual Texas Environmental Law Journal Symposium, University of Texas School of Law, Austin, Texas, April 24, 2015.
  • “Environmental Compliance Strategies,” Hispanic National Bar Association Corporate Counsel Conference, San Antonio, Texas, March 20, 2015.
  • “Environmental Update: Due Diligence and Other Issues for Loan Arrangers,” University of Texas School of Law Mortgage Lending Institute, Dallas, Texas, October 2-3, 2014.
  • “Drilling Down, Environmental Diligence in Oil and Gas Fields,” Environmental Impacts of Oil and Gas Development 2014, State Bar of Texas CLE, San Antonio, Texas January 31, 2014.


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