Karen Leo Mintzer

Karen Mintzer is an environmental lawyer with more than 25 years of experience both in private practice and in the public sector. Her clients include business owners, real estate developers, government agencies and not-for-profit institutions. She manages environmental reviews and obtains environmental permits for large and small development projects, litigates environmental cases, defends clients in environmental enforcement matters, and advises on regulatory compliance, contaminated site remediation, brownfield redevelopment, and business transactions involving environmental issues.


Karen is skilled at providing her clients with strategic, results-oriented advice. She knows how to manage and work cooperatively with interdisciplinary teams and varied constituencies, both inside and outside of government, to help her clients accomplish their goals.


Through 2014, Karen was a Special Counsel in the environmental practice group at Kramer, Levin, Naftalis and Frankel LLP, where she worked closely with the firm’s land use, real estate and corporate practice groups. In 2015 she left private practice to become Regional Attorney - General Counsel to the New York State Department of Environmental Conservation in Region 2 (covering New York City). In 2018, she was appointed by Governor Andrew Cuomo to serve as General Counsel for the New York State Office of Parks, Recreation and Historic Preservation, a position she held until becoming a founding member of Mintzer Mauch PLLC in 2020.  

Karen’s work in New York State government expanded her knowledge of environmental law, and gave her additional expertise in public-private partnerships, construction, alienation, historic preservation, legislation, insurance, procurement, concessions, state finance law, government grants, public officers law and government ethics.  

Karen lives in Brooklyn with her husband, two teenage sons, and their dog, Louise.


Georgetown University Law Center, J.D.

Lafayette College, B.A.


Bar and Court Admissions:

State of New York 

United States District Court, Southern District of New York

United States District Court, Eastern District of New York

United States District Court, Northern District of New York


New York State Bar Association, Real Property and Environmental and Energy Law Sections 

New York City Chapter Board Member, New York League of Conservation Voters

(212) 380 6170


Helen Collier Mauch

Helen Mauch has over 25 years of experience in all aspects of real estate development, environmental law, land use and zoning. Client-oriented and driven to achieve her clients’ goals, Helen provides a high level of engagement, responsiveness and care to every matter.


Helen represents private and municipal clients in environmental compliance and enforcement matters before federal and state environmental agencies, including the New York State Department of Environmental Conservation, United States Environmental Protection Agency, and Army Corps of Engineers, and advises on brownfield cleanup applications, wetland, solid waste management, and other environmental permits.  


Helen also guides private and municipal clients through the full environmental review process under the City and State Environmental Quality Review Act (CEQR/SEQRA), and represents clients in Article 78 challenges to administrative decision-making. 


In addition, Helen provides advice in connection with environmental aspects of real estate and corporate transactions, including transactions involving the redevelopment of brownfield sites, due diligence review, and negotiation of agreements to protect clients from liability. Helen’s experience also includes representation of municipalities and developers in connection with large-scale development projects, public-private partnerships, and drafting complex development agreements.

Outside of New York City, Helen prosecutes land use applications before legislative bodies, planning boards and zoning boards throughout Westchester County and the Hudson Valley region, in order to secure variances, zoning amendments, site plan, subdivision, and special permit approvals. 

Prior to founding Mintzer Mauch PLLC, Helen was a partner at Zarin & Steinmetz in White Plains. She also spent ten years working in the Environmental Department of Rosenman & Colin (now Katten Muchin Rosenman) in New York City, working closely with the land use & zoning, real estate, corporate and litigation departments.

Helen lives with her husband in New Rochelle, where they raised their three daughters. 

(212) 380 6170


Fordham University School of Law, J.D.

Boston College, B.A.

Bar and Court Admissions:

State of New York 

State of New Jersey

United States District Court, Southern District of New York

United States District Court, Eastern District of New York

United States Supreme Court



New York State Bar Association, Environmental and Energy Law Section, co-chair of Environmental Business Transactions Committee

Hudson Valley Legal Services Board Member

We love what we do. We also love a good laugh, spending time with our families, getting together with friends, practicing yoga, skiing, and hiking in the woods. 

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