ONE WOULD hope that any citizen would cross the street to help a dying man. So when those whose very job is to protect the public turn their backs, it is especially horrifying. That is what seems to have happened when D.C. firefighters rebuffed appeals for help for a 77-year-old man stricken by a heart attack outside their station.

“When it’s a cardiac case, seconds matter, and they didn’t help my dad,” said Marie Mills as she tearfully recounted to WTTG-TV (Fox 5) the agonizing minutes it took to get emergency help for her father, who collapsed Saturday across the street from a Northeast Washington fire station. Passersby went to the station, and Ms. Mills screamed for assistance, but the firefighters’ response was that they couldn’t act unless someone called 911.

An ambulance eventually was dispatched from another station and, according to news reports, mistakenly went to an address in Northwest, not Northeast. Ms. Mills told The Post’s Peter Hermann that a police officer eventually flagged down an ambulance that happened to be passing by. Medric Cecil Mills Jr., a veteran of more than 40 years of city government who was still working in the parks department — because, his daughter said, that’s how much he loved the city — died at Washington Hospital Center.

Officials voiced their outrage. Fire Chief Kenneth B. Ellerbe ordered an immediate investigation. Mayor Vincent C. Gray (D) called Ms. Mills and apologized. Firefighters union president Edward C. Smith said “this shouldn’t happen” and offered his own apology “on behalf of all D.C. firefighters.”

Administration officials said no rules or regulations are in place that would have prevented fire department personnel on the scene from taking action. So it’s important to find out precisely what did happen — and whether people need to be held to account. But larger issues about the department’s ability to deliver acceptable emergency medical care are also at play.

The callous disregard for Mr. Mills and the mix-up in addresses are reminiscent of the ineptitude that surrounded the 2006 death of retired New York Times reporter David E. Rosenbaum. Reforms supposedly were put in place following that case, but troubling incidents continue, such as the death of a 71-year-old man who had to wait 30 minutes for an ambulance because a third of firefighters called in sick on New Year’s Day 2013.

Bolder action might be needed in a department with a change-resistant culture. Mr. Ellerbe has had smart reform ideas, but he has been ineffective in getting support for them from the firefighters union or the D.C. Council. Unfortunately, he is not the first fire chief whose tenure has been roiled by infighting and controversy.

We wonder if the District should revisit the possible advantages of spinning off emergency medical care into a separate department since those calls comprise the bulk — more than 80 percent — of the department’s work.

This heartbreaking case should wake up the fire department — rank and file as well as leadership — to the sobering fact that it has become a national embarrassment. It’s a dysfunctional service that the public can’t depend on for needed care — as Ms. Mills tragically learned while she watched her father fight for breath as people trained and paid to provide life support stood by and did nothing.