The Obama administration is set to scale back plans to open Atlantic waters to a new generation of oil and gas drilling, after a revolt by environmentalists and coastal communities that said the activity threatened marine life, fishing and tourism along the U.S. East Coast.

The proposed offshore leasing program walks back the administration’s initial plan to auction off drilling rights in as many as 104 million acres of the mid- and south-Atlantic in 2021, according to an Interior Department official who requested anonymity because the plan wasn’t yet public.

The decision to close the door to expansive Atlantic drilling responded to an outcry from coastal residents and opposition from the Pentagon, which concluded the activity could impede military training and naval exercises. The move also reflects current market dynamics, conflicts with other uses of the ocean and limited infrastructure in the region, according to the Interior official.