Concerns about possible mercury contamination have led to a new lawsuit over plans to destroy an aging stockpile of mustard gas at a remote chemical weapons depot in Oregon.

The Government Accountability Project lawsuit against the Oregon Department of Environmental Quality also seeks review of plans to destroy secondary wastes from the weapons incinerators at the Umatilla Chemical Depot in Hermiston — including plastic protective suits and contaminated carbon filters.

The state agency declined comment.

Richard Condit, attorney for the Government Accountability Project, said Oregon officials have ignored alternatives to burning the obsolete weapons in special incinerators constructed for that purpose at the Army depot.

The main alternative is chemical neutralization of the mustard gas, already approved for other stockpiles at depots in Colorado and Kentucky, Condit said.

“It’s probably the ideal technology for dealing with mercury,” he said.

The Washington, D.C.-based Government Accountability Project won a ruling in April in Multnomah County Circuit Court in Portland ordering the state to review the “best available technologies” to decide the best method of disposing of secondary wastes and mustard gas.

The new lawsuit, filed Tuesday in the same court, challenged a state finding in September that incinerating the weapons and secondary waste “would have no major adverse effect on public health and safety or the environment of adjacent lands,” according to the complaint.

Last week, Congress approved a defense spending bill that would set a 2017 deadline to destroy stockpiles of aging Cold War chemical weapons at depots in Oregon, Alabama, Arkansas, Indiana, Kentucky, Colorado and Utah.

The Oregon depot finished destroying weapons with GB-sarin nerve agent last July and now is working on a stockpile of VX weapons before turning to the 2,635 one-ton containers of mustard blister agent stored at the depot.

Bruce Henrickson, depot spokesman, said it will take about a year and a half to destroy all the VX weapons. So far, everything is going well, he said.

Condit said Oregon law is unique in demanding that the method of chemical weapon disposal be the “best available technology.”

He said the Aberdeen Proving Ground facility in Maryland destroyed 1,800 tons of mustard gas by a neutralization method that mixes the agent with boiling water and bacteria.

“The state has been aware for years of the availability of neutralization to safely and quickly destroy mustard agent and has stubbornly refused to consider the option because the environmental agencies are heavily influenced if not controlled by the Army and its contractors,” Condit said.

Other plaintiffs who joined in the lawsuit include the Sierra Club, the Oregon Wildlife Federation, the nonprofit local watchdog group G.A.S.P. and several individuals who live or work near the depot.