A north Concord-based developer has sued the East Bay Regional Park District, claiming plans for a new regional park on former Concord Naval Weapons Station land would impact the developer’s planned Faria residential development in Pittsburg, immediately east of the park.

The park district, meanwhile, contends the “last-minute, baseless” lawsuit will delay plans to provide public access to the recently approved Concord Hills Regional Park, on the eastern portion of the former weapons station land abutting Pittsburg.

The new regional park is a key element of an ongoing effort to redevelop the weapons station property with 13,000 housing units and millions of square feet of commercial space, along with a college campus and other development.

The suit, filed in Contra Costa County Superior Court by developer Albert Seeno III’s Discovery Builders company and the Faria Land Investors LLC, claims the new 2,540-acre regional park could cause environmental impacts on and near the site, and would impact their planned Faria residential development in Pittsburg, 1,500 single-family houses on a 606-acre parcel adjacent to the ridgeline of the park. That housing project is nearing an approval vote by the Pittsburg City Council.

The Discovery Builders’ suit alleges the park district used 10- to 20-year-old data to inform the environmental impact reports supporting the park project, which could harm animals — including Central California tiger salamanders, California red-legged frogs and Alameda whipsnakes — that inhabit that land.

“The draft environmental impact report fails to sufficiently disclose and analyze impacts to biological resources and greenhouse gas emissions, fails to adequately establish the environmental baseline, and improperly defers mitigation measures,” the suit says.

James Colopy, an attorney representing Discovery, said the builder “has always had concerns about the conversion of a military weapons facility into a public park,” and the potential environmental issues connected to that.

“The (park) district shrugged off our concerns,” Colopy said.

EBRPD spokesman Dave Mason on Tuesday refuted Discovery’s contention that it had tried to be involved in the park process early on.

“Seeno did not participate in the 20-year acquisition and park planning process, the five-year land use planning process, and the nine-month EIR process,” Mason said in an email. “Seeno’s comments were submitted after the EIR’s comment period had ended. Seeno only submitted his objections at the very last-minute, delaying improvements and costing taxpayers tens of thousands of dollars (so far) that would otherwise go toward creating the new park.”

Park district directors in July approved the final land use plan for the Concord Hills Regional Park, which includes a joint visitor center with the National Park Service highlighting the history of the Port Chicago Naval Magazine National Memorial and the history of the Diablo Valley, as well as miles of recreational trails for hiking, biking and nature viewing.

In a statement, park district officials describe the environmental studies for the park project as “thorough.”

“The Seenos will not block the will of the public on this land project,” park district General Manager Robert Doyle said.

Seeno companies have, in the past, been on the receiving end of similar allegations of environmental negligence in that same area.

In January 2008, the California Department of Fish and Game and city of Pittsburg investigated the reshaping of the hills high atop the western portion of the San Marco subdivision — not far from the Faria project — by Discovery Builders, including possible destruction of a seasonal stream. The Contra Costa County District Attorney’s Office ultimately said there was not enough evidence that a stream had been removed.