WHITE PLAINS, N.Y. (CBSNewYork/AP) — Federal regulators on Tuesday said the owners of the Indian Point Energy Center in Westchester County failed to amend a nuclear reactor operator’s license when the man developed sleep apnea.

Apnea prevents restful sleep and causes drowsiness. Investigators found it caused a Metro-North train engineer’s sleepiness in the derailment in the Bronx that left four people dead back in December 2013.

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The Nuclear Regulatory Commission announced Tuesday that it issued a violation to Entergy Nuclear, owner of the Indian Point plant in Buchanan.

An NRC spokesman said the reactor operator never fell asleep at work, and the disorder caused no problems. He said there are always multiple operators on duty.

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He said the license should have been amended to ensure the operator was being treated.

An Entergy spokesman said the operator properly disclosed his condition and the violation was an administrative oversight.

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