Colorado Water District Sues Denver Over PFAS Contamination Allegedly Tied to Fire Training Facility

A Colorado water provider has filed suit against the City and County of Denver, alleging that decades of firefighting training activities at a Denver Fire Department training facility contaminated groundwater supplies with PFAS chemicals used in firefighting foam.

The South Adams County Water and Sanitation District filed suit in U.S. District Court for the District of Colorado against Denver, asserting claims under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). The District seeks to recover past and future costs associated with treating drinking water allegedly contaminated by per- and polyfluoroalkyl substances (PFAS), including PFOS and PFOA, that it claims originated from Denver’s fire training operations. 

According to the complaint, Denver owns and operates its training academy at 5440 Roslyn Street in Denver. The facility has been used by the Denver Fire Department since at least 1991. The District alleges that for decades the fire department conducted live-fire training exercises at the site using aqueous film-forming foam (AFFF), a firefighting foam historically used for flammable-liquid fires and known to contain PFAS compounds. 

The complaint describes training scenarios in which buildings at the facility—referred to as the “Burn House”—were ignited and firefighters were directed to extinguish the fires using PFAS-containing foams. The District alleges that the foam was not adequately captured or contained and instead entered surrounding soil, surface water, and groundwater. 

The District further alleges that the fire training facility sits hydraulically upgradient from its drinking-water wells. According to the complaint, groundwater beneath the training facility flows downgradient through subsurface features, including the Quebec Paleochannel, ultimately reaching the District’s wellfields in Commerce City. 

PFAS contamination in the District’s raw water supplies was discovered in 2018, when testing of 24 samples from District wells detected combined PFAS concentrations ranging from 24 parts per trillion (ppt) to as high as 2,280 ppt, including elevated levels of PFOA and PFOS. Under the U.S. EPA’s final National Primary Drinking Water Regulation issued in April 2024, the maximum contaminant levels for PFOA and PFOS are each 4.0 ppt. According to the complaint, the District promptly notified state and federal regulators and the City and County of Denver of the contamination and immediately undertook measures to ensure that finished drinking water delivered to customers remained within applicable regulatory standards.

The complaint includes detailed allegations regarding sampling conducted at and near the fire training facility. According to the District, groundwater samples collected by Denver in March 2019 showed PFOS concentrations as high as 44,000 ppt and PFOA concentrations exceeding 10,000 ppt in monitoring wells near the facility. Additional sampling conducted in 2022 and 2024 allegedly confirmed continued high concentrations of PFAS in soil and groundwater at and downgradient of the training site. 

As a result of the alleged contamination, the District claims it has incurred tens of millions of dollars in response costs. These include implementing intensive treatment using granular activated carbon, purchasing treated blending water from Denver Water, expanding water-quality monitoring, developing in-house PFAS testing capabilities, and constructing a new dedicated PFAS treatment facility using ion-exchange technology. The District alleges these costs were necessary to continue providing potable water to approximately 75,000 residents served by more than 24,000 connections. 

The lawsuit asserts that PFOS and PFOA are now designated as hazardous substances under CERCLA and alleges that Denver, as owner and operator of the fire training facility at the time of disposal, is a “covered person” responsible for the release of those substances. The District seeks recovery of past response costs and a declaratory judgment establishing Denver’s liability for future costs associated with the ongoing contamination. 

Here is a copy of the complaint: