Community groups that oppose the controversial $1.2 billion expansion of Interstate 70 through northeast Denver have asked the U.S. Department of Transportation to investigate potential civil rights violations in the state’s plan.

The request on Tuesday to the USDOT’s Office of Civil Rights is based on the likelihood that the Elyria-Swansea neighborhood, which is nearly 84 percent Latino, will bear the brunt of the project’s negative impact. The project calls for the widening of Interstate 70 with the addition of tolled express lanes and frontage roads, plus the lowering of the elevated highway below grade between Brighton and Colorado boulevards.

The civil rights complaint is the second front in opponents’ legal war against I-70. In March, the Sierra Club filed a still-pending lawsuit challenging recently changed federal air quality standards that allow for the project to move forward.

Both actions are aimed at delaying the project as well as forcing officials to consider significant modifications. As it stands, CDOT and federal officials plan early next year to issue a Record of Decision that will mark the end of an exhaustive environmental review and the official green light for construction.

The new civil rights complaint was filed by the Denver office of Earthjustice, an environmental law firm. It is representing the Colorado Latino Forum, the Elyria and Swansea Neighborhood Association, and the Cross Community Coalition.

While the Colorado Department of Transportation contends that more than a decade of planning for the I-70 project has resulted in a range of measures — including a 4-acre landscaped cover over part of the below-grade highway — that will reduce its effects, the groups argue CDOT hasn’t gone nearly far enough.

They again raise CDOT-rejected alternatives that would involve rerouting all or some of I-70’s traffic to interstates 270 and 76 to avoid tripling I-70’s footprint.

Ultimately, the complaint says, CDOT faces the obligation under a federal civil rights law of addressing the depressed property values, pollution and other ills wrought by I-70 five decades ago when the current viaduct bisected Elyria-Swansea.

“It’s an opportunity for the state, the city and the feds to right an injustice that was done to us,” said Candi CdeBaca, the founder of Cross Community Coalition and executive director of Project VOYCE. “Other options exist. Our intent with this complaint is to show that the alternatives were narrowed down to three inequitable alternatives without community input.”

Earthjustice’s 33-page complaint and request for an investigation cites a statewide transportation plan adopted by CDOT in May. Its I-70 design “will result in disparate and severe environmental and economic impacts on the predominantly Latino communities of Elyria-Swansea and Globeville,” the document says.

In coming weeks, the federal agency will consider the new complaint and whether to investigate the claims pressed by the groups — many of which they have raised previously.

“CDOT stands behind the last 13 years of analysis and work with the community to find a solution for I-70 that addresses an aging and congested highway while also reconnecting communities,” said a statement provided by project spokeswoman Rebecca White. “CDOT’s engagement with residents and businesses as well as the commitments we’ve made, including a 4-acre park over the interstate (and) improvements to the community, homes and school, are unprecedented and reflect the department’s intention to transform I-70 for travelers and adjacent neighborhoods.”

The community groups’ new complaint deems CDOT’s plans insufficient.

Those include providing storm windows and air conditioners to keep construction dust out of homes, relocation assistance for dozens of displaced homeowners and renters, and $2 million for affordable housing programs.

The complaint says concerns still not fully addressed include increased air pollution from the highway, the likelihood that displaced residents can’t afford soaring housing costs elsewhere, and the disturbance of contaminated soil by the project and related drainage systems. They also cite the removal of street crossings across I-70, the need for more noise barriers and the potential loss of property values in the neighborhoods during the years-long construction period.

“We are asking the U.S. Department of Transportation to recognize and remedy the heavy cost that these communities have paid in reduced life expectancy, illnesses like childhood asthma and cardiovascular disease, and depressed property values,” said Heidi McIntosh, a Denver-based Earthjustice attorney, in a news release issued Wednesday. “These communities have suffered unfairly from the burdens imposed by I-70 in their backyard.”