The Obama administration on Monday eased new environmental barriers to some oil and gas deepwater projects, but companies will still have to meet stringent regulations before drilling resumes.

Oil companies and Republican lawmakers have complained that regulations imposed after the BP oil spill have brought Gulf of Mexico drilling to a standstill.

The department’s decision to waive some environmental requirements comes as Noble Corp announced that Marathon Oil Co

canceled a four-year, $752 million contract for a deepwater rig in the Gulf due to lack of drilling permits.

The policy will impact 13 companies with projects that were already underway when the department imposed its ban on deepwater drilling. Companies will be able to forego additional environmental reviews depending on new calculations of the worst-case flow rate estimates for their wells.