Practice Areas


  • Loyola Law School, J.D., Executive Editor of the Loyola International and Comparative Law Journal and member of the St. Thomas More Honor Society

  • University of California, Los Angeles, B.A., English Literature

State Bar Admissions

  • California

Aaron P. Allan

t:  310.282.6279
f:  310.556.2920
  • Vcard:
  • Connect:
  • Download Full Bio:

Aaron P. Allan, a Senior Partner in Glaser Weil’s Environmental & Energy Department, has for more than two decades litigated cutting edge and “bet the company” cases for a diverse range of business entities, including significant environmental and insurance coverage cases, toxic tort cases and real property litigation matters.

Aaron has long represented water utilities accused of delivering contaminated drinking water and many other companies subjected to claims brought under CERCLA and other environmental laws. He has also represented manufacturing companies, government entities, shopping centers, hoteliers, oil companies, solar energy companies, financial institutions, trustees and real estate developers. These representations have often involved complex insurance coverage issues and Aaron has successfully helped clients to obtain full coverage for such lawsuits. In addition to providing advice and counseling on environmental regulatory matters, such as air permitting, asbestos removal, drum recycling, Prop. 65 compliance and hazardous material management, Aaron helps clients manage environmental due diligence, environmental site remediation activities, and liability risks associated with the sale, purchase or foreclosure of environmentally contaminated properties.

As reflected in the list of “Representative Matters” provided below, Aaron has routinely assisted clients with the following types of litigation and counseling matters:

  • Complex Environmental Litigation
  • Real Property Litigation
  • CERCLA/Superfund and Groundwater Cleanup Matters
  • Drinking Water Contamination Claims
  • Solar Power Construction and Energy Credit Issues
  • Proposition 65 Defense and Counseling
  • Asbestos/Mold/Lead Compliance, Litigation and Counseling
  • Insurance Coverage (Including Acquisition, Negotiation and Enforcement)
  • Toxic Tort Defense
  • Air Quality (Including Enforcement Defense and Permitting)

Aaron is also a musician and an avid mountain biker.

  • Loyola Law School, J.D., Executive Editor of the Loyola International and Comparative Law Journal and member of the St. Thomas More Honor Society

  • University of California, Los Angeles, B.A., English Literature

  • California

  • Complex Environmental/Real Property Litigation

  • Successfully defended aluminum and titanium forging company against storm water discharge allegations and Clean Water Act enforcement.

  • Successfully represented drum recycling company accused of criminal conduct and resolved civil statutory penalties for violating storm water discharge laws.

  • Prosecuted multiple cost recovery actions concerning environmentally contaminated properties in Central California on behalf of one of California’s largest ever Chapter 11 bankruptcy estates.

  • Successfully prosecuted and resolved claims brought by owner of Southern California solar energy project against multiple parties based on construction disputes.

  • Represented local government entity to resolve claims against adjoining landowner, involving more than 20 parties, including bankruptcy trustee and probate administrators.

  • Represented large, well-known oil companies to resolve the responsibility for cleanup of contaminated real property located in Central California.

  • Represented large well-known hotelier and successfully resolved flood damage claims based on historic California storm incidents, including 500-year storm.

  • Represented shopping center developer in claim against national chain based on failure to comply with contract requiring store opening.

  • Defended and successfully resolved indemnity claim based on alleged inadequate regulatory closure at former California aerospace facility.

  • Routinely advise companies with respect to acquisition of brownfield sites and due diligence issues arising in connection with real property acquisitions.

  • CERCLA/Superfund/Groundwater Cleanup

  • Currently prosecuting CERCLA and related common law claims against major oil company involved in remediating open-pit mining operation at a federal Superfund site, including issues related to acid mine drainage, continuing tort theories, water rights and restoration damages.

  • Successfully resolved, after federal court trial, claims against a municipality arising under CERCLA based on groundwater contamination caused by leaking sewer.

  • Successfully defended CPUC-regulated water utility in proceedings brought to enforce environmental cleanup obligations relating to groundwater pumping and plume control.

  • Currently representing CPUC-regulated water utility in cost recovery negotiations for groundwater basin cleanup effort being managed by U.S. EPA.

  • Represented insurance company in subrogation action to successfully recover cleanup costs from the United States Department of Defense.

  • Representing CPUC-regulated water utility in appeal from order determining allocation of groundwater pumping rights among over a hundred California entities.

  • Assisted trust department of a large local bank to resolve environmental remediation issues for all properties being managed by the bank, including advice concerning potential lender liability protections under CERCLA and similar state laws.

  • Drinking Water Contamination Claims

  • Developed and successfully briefed to the California Supreme Court the immunity which the Court afforded to CPUC-regulated water utilities in Hartwell v. Superior Court, 27 Cal.4th 256 (2002) based on the delivery of contaminated drinking water.

  • Successfully defended regulated water utility against wrongful death claim based on alleged exposure to E. coli in connection with replacement of drinking water main.

  • Successfully defended and resolved toxic tort claims against water utility.

  • Counsel utilities based on pipe corrosion and related drinking water claims.

  • Routinely counsel California water utilities on drinking water and groundwater issues.

  • Asbestos/Mold/Lead 

  • Currently defending major machinery company against asbestos personal injury claim.

  • Successfully defended well-known hotelier against mold personal injury claim brought by tenant.

  • Counsel clients regarding lead paint exposure and removal issues.

  • Draft protocols for handling lead and asbestos during construction, renovation and demolition activities.

  • Insurance Coverage

  • Represented insurance company in seeking contribution from other insurers in connection with food contamination claim.

  • Represented excess insurance carrier in prosecuting a bad faith subrogation action brought against primary carrier resulting from a $24 million personal injury verdict.

  • Routinely provide advice, counseling and representation in negotiating and enforcing insurance coverage for environmental and real property claims.

  • Proposition 65 Defense and Counseling

  • Successfully defend and settle Prop. 65 enforcement claims.

  • Counsel clients regarding Prop. 65 compliance issues, including new regulations.

  • Evaluate client products and operations for Prop. 65 and other regulatory risks.

  • Air Quality Enforcement and Permitting

  • Represented major hotelier in resolving air permitting issues for one of the largest hotel developments in the world.

  • Successfully resolved regulatory enforcement claims brought by the California Air Resources Board based on alleged violation of consumer products emission standards.

  • Counsel clients and negotiate with state and local agencies regarding diesel truck and generator emission issues.

  • "500 Leading Litigators in America," Lawdragon, 2022, 2024

  • "Litigation Star" (US-National, California), Benchmark Litigation, 2020 - 2022