Mark Elmendorf

Principal Scientist



Hazardous Material Release/Exposure Consulting

Class Action Cases Involving Hazardous Material Exposures

Clean Air Act Compliance

Hazardous Material Storage and Handling

Air Dispersion and Receptor Modeling Studies

Process Hazard Analysis and Root Cause Studies

Environmental Impact Statements


MS, Environmental Science - Hunter College (in progress)

BS, Environmental Science - SUNY College of Environmental Science and Forestry

Mark Elmendorf

Principal Scientist

Mark Elmendorf, Principal Scientist, has over thirty years of experience in environmental consulting with an emphasis on regulatory analysis, vapor intrusion issues, air quality modeling/permitting issues, process safety management, and risk management programs. He has provided Expert Witness services to clients throughout the United States on both environmental litigation and environmental insurance coverage related matters. Expert services have included evaluation of intrusion pathways to determine the root cause of water damage claims, determining the age of water damage, and appraisal of appropriate remedy for final cure of remediation. Mr. Elmendorf has presented training programs on behalf of state agencies on various engineering and compliance requirements. He has extensive experience in process hazard analysis and root cause studies focusing on the chemical industry use, storage, and processing of hazardous materials.

representative projects
  • Principal-in-Charge for major Contaminant cleanup at Brookhaven National Laboratory in New York State. Responsible for the development and implementation of procedures during the excavation and processing of radiological, chemical, biological, and high hazard materials. This project included the oversight of ten safety professionals and sixty remediation workers.
  • Principal-in-Charge providing expert services for a major class action case associated with a catastrophic release of a dense chemical mixture. The impact area exceeded 20 miles from the facility and included several jurisdictions. Provided expert services and deposition on key scientific issues representing the State Department of Environmental Quality.
  • Principal-in-Charge providing expert services for a major class action certification motion. Case involved school age children seeking damages against a large school district. Client was several third-party contractors, which were involved in construction of the school buildings. Provided expert services and deposition on key scientific issues associated with microbial levels within the schools.
  • Principal-in-Charge for a project to prepare an Environmental Impact Statement for an 80-acre truck engine plant. This included research of potential issues associated with the proposed action. Tasks included contacting local agencies, field surveys, and engineering studies to document compliance. Environmental Impact Statement (EIS) sections included hazardous material management, natural resources, water issues, air issues, drainage, and wetlands. Roux then prepared a comprehensive report, which detailed the findings of the evaluation.
  • Principal-in-Charge for completion of a Title V Operating permit at a major pharmaceutical research and development (R&D) facility. The project included over 400 point sources, including pilot plant batch operations involving a variety of unit operations. Process equipment included filtration units, centrifuges, reaction, and evaporation vessels, dryers, and heat exchangers, as well as specialized organic synthesis processing equipment.
  • Principal-in-Charge for the preparation of an OSHA Process Safety Plan for a complex toll batch production chemical plant. Applicable processes at the facility included high-pressure, high-heat reactors, distillation reactors, and vacuum systems. Developed PHA, SOP, change management, and BMP components for plant management.
  • Emhart Industries, Inc. et al. v. New England Container Company, et al., C.A. Nos. 06-2018-S and 11-0023-S. Case involving cost allocation and source determination of PCB usage at multiple locations. The expert services were in connection with certain claims clients in the Litigation related to contamination at the Centredale Manor Superfund Site in North Providence, Rhode Island Prepared two separate Expert reports. Deposition taken on October 17, 2023.

  • United States District Court Middle District of Pennsylvania, United States of America V. First Capital Insulation, Inc., Francis Richard Yingling, Jr., Lobar, Inc., D Nnis Lee Charles, Jr., M & J Excavation, Inc., John August Sidari, Jr., And Ty Allen Barnett, CRIM.NO. 1:20 -CR-020, Criminal Case involving six counts of the National Emission Standards for Hazardous Air Pollutants {"NESHAP”) 42 U.S.C. § 7412. Expert Services, Trial Consultant during trial, Trial Testimony June 1, 2022. Jury verdict of not guilty on all six counts.

  • Civil District Court for the Parish of Orleans, Sheila Guidry, Individually and On Behalf of All Others Similarly Situated Vs. Dow Chemical Company, ET AL, No. 09-7832, Division “K”. Class action involving hazardous material exposure from catastrophic release. Developed expert reports and presented technical opinions during mediation that resulted in favorable settlement.

  • Board Of Land and Natural Resources State of Hawaii in The Matter of Healy Tibbitts Builders, Inc. Barge Anchoring Outside the Honolulu Harbor Entrance Channel, Island of Oahu. Settlement Agreement Negotiation support, expert services for multi-million-dollar claim related to extensive coral damage and restoration.

  • Morgan City Land and Fur Company, L.L.C. Versus Tennessee Gas Pipeline Company, L.L.C., Et Al, 25th Judicial District Court for The Parish of Plaquemines, State of Louisiana, Docket No. 64-754. Case consultation, Expert Report. Property damage related to pipeline damages of marsh areas.

  • Ace American Insurance Company Vs. First Call Environmental, LLC. United States District Court for The Eastern District of Pennsylvania. Civil No. 5:21-Cv-02331-JMG. Expert Report. Hazardous material exposure and property damage related to catastrophic nitric acid release and fire.