Shell's company logo is pictured at a gas station in Zurich April 8, 2015. REUTERS/Arnd Wiegmann

WASHINGTON (Reuters) - A group of 18 mostly Democratic U.S. senators on Friday urged the Obama administration to stop Royal Dutch Shell’s preparations for oil exploration in the Arctic, saying the region has a severely limited capacity to respond to accidents.

The senators, from both coasts and several Midwestern states, sent a letter to Interior Secretary Sally Jewell, urging her to retire Arctic leases in the Chukchi Sea.

Jewell’s department earlier this month conditionally approved Shell’s exploration plan in the Arctic. The move means the company is likely to return to the Chukchi Sea this summer for the first time since a mishap-filled drilling season in 2012.

When Shell lost control of a drilling rig that year it “put numerous lives at risk, including those of the Coast Guard crews” and those of 18 people on the rig, the letter said. The appeal was spearheaded by Senator Jeff Merkley of Oregon and the letter was signed by other liberals, including Dick Durbin of Illinois and Bernie Sanders of Vermont, an independent.

The senators also said drilling in the Arctic contradicted President Barack Obama’s efforts to limit emissions linked to climate change.

Shell CEO Ben van Beurden vowed to keep exploring the Arctic at an annual general meeting this week in the Netherlands, saying that new sources of oil must be developed to keep up with global demand.