A lack of adequate testing for a pernicious sleep disorder was the primary cause of two serious train crashes in New Jersey and New York, federal investigators concluded in a report today as they renewed the call for the testing to be mandatory.

The crashes involving a New Jersey Transit train at the Hoboken terminal in September 2016 and a Long Island Rail Road train in Brooklyn in January 2017 killed one person, injured more than 200 and caused more than $11 million in damage.

In both instances, the train engineers were found to have suffered from undiagnosed sleep apnea, a condition connected to obesity that robs sufferers of sleep and contributes to daytime drowsiness.

The NTSB blamed New Jersey Transit for not following its sleep apnea guidelines and blamed the Long Island Rail Road for not having testing in place before the accidents. It also blamed the Federal Railroad Administration for not making sleep apnea testing mandatory.

The NTSB also faulted both railroads for not considering end-of-track accidents as a potential hazard despite similar, albeit far less serious, incidents over the previous 10 years.

Last year, the FRA abandoned plans to require the testing as part of President Donald Trump’s effort to reduce federal regulations, instead leaving it up to individual rail operators. Senate Minority Leader Chuck Schumer of New York and New Jersey Sen. Cory Booker, both Democrats, countered the Republican president’s move by introducing legislation that would force the testing to be mandatory.

In the Brooklyn and Hoboken crashes, neither engineer could remember his train accelerating as it approached the station and smashed into the end of the tracks.

In the Hoboken crash, a woman standing on the platform was killed by falling debris.

“The public deserves alert operators. That’s not too much to ask,” National Transportation Safety Board Chairman Robert Sumwalt said today.

The NTSB has cited sleep apnea in the probable cause of 10 highway and rail accidents in the past 17 years, including an undiagnosed case in the engineer of a Metro-North Railroad commuter train that sped through a curve and crashed in New York in 2013, killing four people.

Inadequate screening and treatment has “led to worker impairment, collisions involving tens of millions of dollars in damage, and loss of life,” Dr. Nicholas Webster, an NTSB medical officer, told board members today.

NJ Transit had a sleep apnea screening program at the time of the Hoboken crash, but engineer Thomas Gallagher’s most recent available screening form was from 2013 and he wasn’t referred for a sleep study despite displaying some of the necessary criteria, Webster said today. The LIRR, operated by the Metropolitan Transportation Authority, started its screening program after the crash.

“The MTA has an established and aggressive sleep apnea screening and treatment program for all train and bus operators and locomotive engineers in line with the NTSB’s recommendations and we are moving forward with this program, even in the absence of a federal mandate,” MTA spokesman Aaron Donovan said today.

It also noted that the bumping blocks — the concrete-and-steel barriers where the end of the track meets the platform — at both locations couldn’t provide adequate protection from an oncoming train. The bumping block at Hoboken was more than 100 years old; NJ Transit is installing new blocks with more modern safety features.

While U.S. railroads are under a Dec. 31 FRA deadline to install an automatic braking system called positive train control on their tracks, NJ Transit and the LIRR have asked for, and received, exemptions from installing it in the terminals where the crashes occurred, NTSB investigator Ruben Payan told board members today.

The braking system is primarily designed for high-speed train separation and not for a confined, low-speed area like a terminal, Payan said. He added that federal rail officials have been investigating other technologies to use in terminals.

An NJ Transit spokeswoman said the agency is “developing a technology solution” to keep trains from speeding at terminal stations. After the accident, NJ Transit began having a conductor ride in the cab car with the engineer, and reduced the speed limit restrictions coming into Hoboken from 10 mph to 5 mph.