Environmental groups yesterday filed a motion in a closely watched chemical dispersants lawsuit that seeks to prevent the largest oil and gas industry group from getting involved in the case.

At issue is a lawsuit filed in August that seeks to force U.S. EPA to rewrite regulations governing the use of dispersants like those deployed in the 2010 Deepwater Horizon spill.

The American Petroleum Institute has filed a motion to intervene in the case, which involves environmental groups from the Gulf of Mexico and Alaska.

Hannah Chang, an Earthjustice attorney representing the groups, said the court should reject API's filing.

"We want the federal government to comply with the Clean Water Act to make sure that only dispersants that are safe for humans and the environment are used in the event of an oil spill," she said. "We don't need [API] to be involved in this case arguing to maintain the status quo and pushing to weaken rules that should be more protective."

API was unable to provide a response in time for publication.

Specifically, the groups essentially argue that API lacks standing in the case.

"API fails to demonstrate that its members actually or will suffer concrete and particularized injuries necessary for standing and intervention," they wrote.

The safety of the chemical dispersants has long been a concern for public health advocates. Following the 2010 Gulf of Mexico spill, 1.8 million gallons of the dispersants was used to break up oil into droplets that bacteria and other marine organisms can eat. The dispersants helped keep oil from contaminating coastal marshes.

But the science remains inconclusive on how the dispersants themselves affect delicate ecosystems. EPA wavered about how much of the dispersants to use in the Gulf following the spill, resulting in a back-and-forth with BP PLC (Greenwire, April 22, 2011).

EPA Administrator Lisa Jackson has said previously that more research needs to be conducted on dispersant safety and said the agency is "committed to revisiting" the issue (Greenwire, Sept. 28, 2010).

Currently, EPA produces a national contingency plan that includes what dispersants are authorized to be used in oil spills. The lawsuit alleges that EPA fails to provide data on which dispersants can be safely used in specific water bodies as required by the Clean Water Act (Greenwire, Aug. 7).

The groups that filed the case are the Louisiana Shrimp Association, the Florida Wildlife Federation, the Gulf Restoration Network, the Louisiana Environmental Action Network, Alaska-based Cook Inletkeeper, Alaska Community Action on Toxics, the Waterkeeper Alliance and the Sierra Club.