Montrose Environmental Group was founded in 2012, received investment from
Oaktree Capital Management in 2018, and began trading on the
New York Stock Exchange in July 2020. In 2019, Montrose subsidiary, Enthalpy Analytical, performed PFAS water testing for the town of
Maysville in
Jones County, North Carolina. The company has performed similar testing for various municipalities and agencies, including
Pender County, North Carolina. Enthalpy Analytical was also a contributor to a study titled, "
Analysis and differentiation of tobacco-derived and synthetic nicotine products" published in
PLOS One. In 2021, the company moved its corporate headquarters from
Irvine, California, to Little Rock, Arkansas. Arkansas Secretary of Commerce Mike Preston welcomed the company and wrote that "Montrose will be a great addition to the Arkansas business community" and Governor
Asa Hutchinson wrote "I am confident that Montrose will find the [Arkansas] talent they need to grow and prosper for many years to come." By 2020, Montrose subsidiary ECT2's water filtration and PFAS removal vessels had been deployed to more than 350 sites around the world and have supported water filtration efforts with various municipalities such as the city of
Portsmouth, New Hampshire and the Anson-Madison Sanitary District. ECT2 has also deployed a patented resin system at the site of
Pease Air National Guard Base which has treated tens of millions of gallons of contaminated water. In June 2022, Montrose was the victim of a "highly sophisticated" ransomware attack that impacted computers and servers within the company's Enthalpy Analytical laboratory network. In 2023, Montrose representatives were selected to serve on a technical panel to support the development of new, enhanced air monitoring guidance for the State of Colorado Department of Public Health & Environment, Air Pollution Control Division. The company has also been represented at the
U.S. Environmental Protection Agency (EPA) National Ambient Air Monitoring Conference. In the aftermath of the 2023
East Palestine, Ohio,
train derailment, railroad company
Norfolk Southern hired Montrose subsidiary CTEH to address residents' concerns about health risks, design the testing protocol for the indoor air tests, run a resident hotline regarding fears of odors, fumes or health problems (working closely with the EPA), and publish an Air Sampling and Analysis Plan. The same year, CTEH was contracted by
Miami-Dade County to conduct air monitoring after a massive fire at the County Waste-to-Energy Facility. Montrose has also been contracted by the
California Public Utilities Commission to help organizations and companies in the state maintain
California Environmental Quality Act (CEQA) compliance. The company has also adopted sustainability goals in alignment with the United Nations
Sustainable Development Goals. As of 2024, Montrose has supported over 13 U.S. federal agency clients, including the Army, Air Force, Navy, Coast Guard, Maritime Administration, EPA,
Department of Veterans Affairs,
Food and Drug Administration,
National Park Service,
National Oceanic and Atmospheric Administration,
Centers for Disease Control,
Bureau of Land Management,
National Institutes of Health, and the
U.S. Fish and Wildlife Service. In October 2024, Montrose was awarded a five-year, $249 million contract from the
U.S. Army Corps of Engineers to provide environmental support to the Mobile District, South Atlantic Division, including addressing air and water quality, PFAS, pollution prevention, and hazardous waste. ==Operations==