NEW YORK (CBSNewYork/AP) — Conductors and engineers with the Long Island Rail Road and Metro-North will be required to undergo testing for sleep apnea, Gov. Andrew Cuomo announced Tuesday.

The move comes after a Metro-North engineer with undiagnosed sleep apnea fell asleep at the controls and failed to slow down for a sharp curve in December 2013. Four people were killed and more than 70 were injured when the train derailed in the Spuyten Duyvil section of the Bronx.

The Metropolitan Transportation Authority began testing some Metro-North engineers as part of a pilot program in 2015 and Cuomo said as a result, some participants were required to undergo treatment for sleep apnea.

The screening program will now become permanent and is expanding to include Metro-North conductors and LIRR engineers.

PHOTOS: Metro-North Derailment

“This program helps us identify workers who may be at risk for sleep apnea, ensure they receive appropriate treatment, and ultimately create a safer MTA,” Cuomo said in a statement. “A healthy workforce is crucial to the MTA’s success and, with the expansion of this successful program, we will continue to build a stronger transportation system and keep New York moving forward.”

Sleep apnea disrupts respiration and interferes with a person getting adequate rest.

William Rockefeller, the engineer involved in the fatal derailment, has not worked since the crash and is now receiving a disability pension. Criminal charges were not filed against him.

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