Relatives of a killed coal miner. A coal mine explosion in eastern United States killed five miners but another miner managed to get out alive, the Fox News reported Saturday. (Xinhua)

WASHINGTON, May 20 (Xinhua) -- A coal mine explosion in eastern United States killed five miners but another miner managed to get out alive, the Fox News reported Saturday.

    The incident took place in Darby Mine No. 1 in Harlan County, Kentucky, between midnight Friday and 1 a.m. Saturday (0400 and 0500 GMT) while a maintenance shift was on duty.

    No cause has been found yet, state Governor Ernie Fletcher said.

    Rescuers initially found three dead workers and later recoveredtwo more bodies. Another miner was able to walk out alive and was immediately sent to hospital, but his condition remained unknown.

    Amy Louviere, a spokeswoman for the U.S. Mine Safety and HealthAdministration, said she didn't know how many workers were working when the explosion occurred, but no production was made during the incident.

    The underground mine, operated by Kentucky Darby LLC, is located in a mountainous area near the Virginia state border.

    Mine safety issues have been a major concern for U.S. lawmakers recently, after two accidents in January killed 14 West Virginia coal miners.

    Earlier this week, a key Senate committee endorsed a bill to make coal mining safer, requiring miners to bring at least two hours of oxygen available instead of one as under the current policy. It also required mines to have two-way wireless communications and tracking systems in place within three years. Enditem