Mark Johnson

Mark Johnson is a Principal Consultant based in Maryland with more than 23 years of experience focused on transactional support, site investigation and remediation, subsurface vapor intrusion to indoor air, environmental management assessment and systems, and brownfield redevelopment planning and design. Mark has conducted and managed hundreds of Phase I and Phase II site assessments and compliance audits at industrial, manufacturing, and commercial facilities in the United States, Canada, Latin America, South America, Europe, Asia, and Australia.


As part of his practice, he assists industrial, commercial, and attorney clients in evaluating potential future environmental remediation requirements and costs associated with industrial facilities as part of due diligence and related transaction support, as well as for insurance clients in evaluation of cost recovery claims. Mark develops cost estimates for resource planning, establishing financial reserves, insurance, litigation matters, and third-party negotiations. He routinely provides his clients with environmental cost estimates through the implementation of environmental liability valuation (ELV) services and utilizing multiple software platforms including RACERTM.

As a consultant, Mark has developed numerous remedial investigation work plans and reports, baseline human health risk assessments, feasibility reports, and remedial action closure reports under a variety of state-lead enforcement programs including underground storage tank and voluntary clean-up programs. His current focus is assisting commercial and attorney clients as part of due diligence, evaluation of cost recovery claims, and litigation support. He currently manages several Multi-District Litigation (MDL) products liability and toxic tort engagements. In addition, Mark has been instrumental in assisting a Fortune 500 client with technical support during the settlement of a Consent Decree related to groundwater and surface water conditions while managing several of its large site investigation and remedial planning projects.

He has designed and implemented various remedial technologies, including enhanced aerobic bioremediation, soil excavation, soil vapor extraction, dual-phase extraction, and in situ chemical oxidation. He specializes in earth sciences, hydrogeology, and environmental engineering. Earlier in his career, he managed numerous environmental claims and ongoing litigations including toxic tort, asbestos, pollution, chemical exposure, and hazardous waste claims for a leading insurance carrier. Mark has experience supporting numerous government-sector site investigation and remediation projects for the U.S. Army Corps of Engineers (USACE) and U.S. EPA.

Contact Mark Johnson at This email address is being protected from spambots. You need JavaScript enabled to view it. or +1-410-381-4333.

Career Summary: Mark Johnson

  • Specialties: Site Investigation and Remediation; Groundwater Assessment and Remediation; Subsurface Vapor Intrusion to Indoor Air; Environmental Management Assessment and Systems; Brownfields Redevelopment Planning and Design
  • Practice Areas: Contaminated Site Assessment and Cleanup
  • Disciplines: Earth Sciences, Environmental Engineering, Hydrogeology
  • Education: M.S., Environmental Engineering, University of Maryland at College Park, 2004; B.A., Earth and Planetary Sciences, The Johns Hopkins University, 1995
Geosyntec Consultants
Geosyntec is a consulting and engineering firm that works with private and public sector clients to address new ventures and complex problems involving our environment, natural resources, and civil infrastructure.

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