A group of 37 U.S.-based scientists whose research focuses on Arctic wildlife asked two U.S. senators in a letter on Thursday not to open the National Arctic Wildlife Refuge to oil and gas exploration, according to a copy seen by Reuters.

The scientists, including several retired former officials from the Alaska Department of Fish & Game, the U.S. Geological Survey and the U.S. Fish & Wildlife Service, said in a letter to Sen. Lisa Murkowski of Alaska and Sen. Maria Cantwell of Washington that drilling for oil and gas in the refuge would be "incompatible with the purposes for which the refuge was established," protecting fish and wildlife populations and the environments in which they live.

Murkowski, a Republican, introduced legislation on Wednesday that would create an oil and gas exploration program on the refuge's coastal plain, letting prospectors build any roads and other infrastructure they deemed necessary inside the refuge to carry out their operations. Half of the available drilling royalties would go to the state of Alaska and half to the federal government. The program's administrator would be required to hold at least two lease sales within 10 years after the bill became law.