With energy companies relinquishing their holdings, advocacy group Oceana said the end may be near for drilling in the Arctic waters offshore Alaska.

Oceana said it's found through a Freedom of Information Act request that companies ranging from ConocoPhillips to Italy's Eni have released their leases in the Chukchi Sea. Shell, which Oceana said is holding on to one lease, has a problematic track record offshore Alaska. A drillship suffered mechanical issues in 2012 and, in July, a breach was discovered in the hull of a vessel meant to carry the safety equipment to the region.

Michael LeVine, the senior regional counsel for the group, said that, after spending "billions of dollars" on Arctic campaigns, energy companies may be realizing the risks aren't worth the reward.

"Hopefully, today marks the end of the ecologically and economically risky push to drill in the Arctic Ocean," he said in a statement emailed to UPI.

The advocacy group filed a motion in January with the U.S. Department of Interior calling for reconsideration of new leases offshore Alaska. Oceana at the time said the "most obvious" risk would be a catastrophe like the oil spill at the Deepwater Horizon rig in the Gulf of Mexico in 2010.

Shell has appealed to U.S. government to hold on to its remaining interests. Federal leases expire at the end of their terms unless operators are engaged in drilling or related activity. Shell's leases would start to expire by next year.

In a statement sent to UPI, a spokesman for Shell said the poor exploration results and the high costs associated with drilling offshore Alaska swayed its decision on area leases.

"In the summer months of 2016, we will remove the remaining equipment from the drilling sites in Alaska," the spokesman said. "We continue to believe offshore Alaska and the broader Arctic have strong exploration potential and are areas that could ultimately be important sources of energy to the state of Alaska, the United States and the world."