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Michael Daneker concentrates his practice on environmental law and toxic tort litigation. Mr. Daneker serves as primary defense counsel in class action and mass joinder toxic tort lawsuits around the United States, including personal injury, medical monitoring, and property damage actions. He also defends federal and state enforcement actions, citizen action suits, CERCLA litigation, Clean Water Act litigation, and natural resource damage claims related to complex contaminated sites.

Mr. Daneker also serves as Co-Managing Partner of the firm.

Mr. Daneker is recognized by both Chambers and the Legal 500 USA and has appeared in nationally prominent matters including PFAS toxic tort litigation, the Deepwater Horizon oil spill in the Gulf of Mexico, New Jersey chrome litigation, and other high profile toxic tort matters.

Mr. Daneker's work often includes both defending litigation and working with the client to develop a long-term strategy for contaminated site resolution, including remedy selection, natural resource damage mitigation, risk transfer mechanisms, and brownfields redevelopment. He often works closely with the client's engineers, technical experts, and public and community affairs personnel to develop a comprehensive litigation, regulatory, political, and scientific solution to the site.


  • BP, as lead outside counsel for the comprehensive investigation of the Deepwater Horizon oil spill, participation in resolution of criminal claims, and lead outside counsel with respect to debarment matters and with respect to the global settlement of federal, state, and local government claims, including natural resource damages.
  • Honeywell, as primary litigation counsel in numerous lawsuits related to more than 130 chromium contaminated sites in New Jersey.
  • A Former uranium processing company, with respect to the remediation of a site containing low level uranium waste materials in Pennsylvania.
  • Various clients at numerous major contaminated sites, including mining and manufacturing sites in Utah, Nevada, Maryland, South Carolina, Ohio, Florida, and Georgia.
  • Manufacturing companies, in advising and assisting in Brownfields redevelopment projects in New York, Maryland, and New Jersey.
  • Numerous clients at sediment sites, including the Lower Passaic, the Gowanus Canal, Onondaga Lake, the Hudson River, the Detroit River, and Berry's Creek.


The Chemical Compound, Summer Edition
Environmental Edge: Climate Change & Regulatory Insights
The Chemical Compound—August 2021
The Chemical Compound—May 2021
The Chemical Compound—February 2021
Legal Updates on High Priority Chemicals and Important Chemical-Regulatory Developments
Arnold & Porter Appoints Ellen Kaye Fleishhacker Co-Managing Partner


The Legal 500 US
Product Liability, Mass Tort and Class Action: Defense — Toxic Tort (2015-2017, 2019, 2021-2022, 2024)
Environment: Litigation (2009-2012, 2015, 2017-2019, 2021-2022)
Chambers USA
Environment (Washington, D.C.) (2013-2024)
BTI Client Service All-Star Attorney (2017)



  • J.D., Vanderbilt University Law School, Founder's Medal
  • M.Phil., Cambridge University
  • B.A., Yale University, summa cum laude


  • District of Columbia
  • Maryland


  • United States Court of Appeals, District of Columbia Circuit, The Honorable Karen Lencraft Henderson