Clarissa Anne Howley Mills

Clarissa Howley Mills is an environmental attorney in Holland & Knight's Dallas office. Ms. Mills focuses her practice on environmental regulatory counseling, enforcement defense, incident and crisis management, environmental due diligence and advising on environmental matters in corporate and real estate transactions. With experience advising clients under nearly every major federal environmental statute and regulatory program, Ms. Mills assists clients developing big-picture strategies on some of the most complex environmental issues facing regulated entities today.

Drawing on nearly a decade of leadership experience at the U.S. Environmental Protection Agency (EPA), Ms. Mills helps clients navigate evolving regulatory frameworks, emergency response incidents, enforcement actions, agency investigations and permitting with a pragmatic, business‑focused approach. She is known for bringing deep institutional knowledge of agency processes and enforcement priorities to help clients anticipate regulatory risk, engage effectively with regulators and reach efficient, durable resolutions.

During her time at EPA, Ms. Mills served as deputy regional counsel for EPA Region 6. In that role, she managed one of the agency's largest regional legal offices and advised senior officials on high‑stakes emergency response and remediation matters, permitting decisions, and federal and state oversight issues across a five‑state region and dozens of federally recognized Tribes. She provided counsel under key environmental statutes, including the Clean Air Act (CAA), Clean Water Act (CWA), Resource Conservation and Recovery Act (RCRA), Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), Safe Drinking Water Act (SDWA), Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), Toxic Substances Control Act (TSCA) and related regulations.

Prior to her deputy role, Ms. Mills served as the lead senior counsel for chemical enforcement actions, where she acted as a national subject matter expert on investigations under the Chemical Accident Prevention regulations, as well as pesticide, toxic chemicals and hazardous waste programs. In that capacity, she led investigations of significant industrial incidents and helped secure settlements totaling tens of millions of dollars in penalties, along with extensive environmental compliance commitments. Accordingly, Ms. Mills is well suited to advise clients in resolving governmental investigations and enforcement actions, including negotiating penalty and compliance orders.

Prior to joining Holland & Knight, Ms. Mills worked for a global law firm in Dallas in its environmental practice group. While there, she counseled clients on environmental regulatory compliance, enforcement defense, litigation, due diligence and transactional matters.