ExxonMobil, which holds permits to drill off the coast of California, has asked the court for permission to intervene in a lawsuit that challenges the federal government’s authority to approve offshore drilling.

The Environmental Defense Center (EDC), a Santa Barbara-based nonprofit law firm, sued the Bureau of Safety and Environmental Enforcement (BSEE) of the Department of the Interior in  December of 2014. The lawsuit claims the agency did not adequately consider the environmental impacts of proposed wells in the Santa Barbara Channel when it approved their development.

The lawsuit, filed with the U.S. District Court for the Central District of California, claims that all 51 approvals by the BSEE violated the National Environmental Policy Act.

In February, the American Petroleum Institute (API) asked to intervene. The EDC has asked the court to allow only the API or ExxonMobil to intervene, not both, arguing that “their interests are directly aligned.”

ExxonMobil contested that argument, noting that it holds 29 of the 51 permits in the channel, which it seeks to protect, while “API’s objective is to protect the diverse interests of its 600-plus members.”