New York ? It was a love affair born of tragedy. For more than two years after the World Trade Center attack, New York City firefighters could do no wrong.

New Yorkers flooded their heroes with homemade cookies and cash donations, gave them rousing ovations in restaurants, even blockaded neighborhood firehouses the city wanted to close.

But firefighters’ golden public image has been tarnished in recent months by allegations of on-duty drinking, firehouse brawling, marital infidelity and drug abuse.

One firefighter smashed another in the face with a metal chair after drinking on New Year’s Eve at their Staten Island firehouse. A surprise raid on an East Harlem firehouse found beer and liquor in a locker and cocaine in two firefighters’ systems.

A captain and a lieutenant were caught drinking beer in uniform in a karaoke bar they were supposed to be inspecting. A firefighter who posed for the fire department’s beefcake charity calendar is facing a departmental steroid charge. He’s also moonlighting as a stripper.

“We have set a high standard for ourselves, and when there’s a couple incidents it’s going to make a big splash,” said Sal Sodano, a retired fire lieutenant.

Some firefighters say lingering trauma from the attacks of Sept. 11, 2001, may be causing some of the trouble. More than 7,000 members of the 11,500-member department have gone to the FDNY’s counseling unit for treatment of anxiety, depression and other problems.

“I think there’s much more emotion going on in the fire service than before 9-11, and God knows how it comes out,” retired deputy chief Vincent Dunn said.

The slew of tawdry headlines began with the revelation that firefighters assigned to counsel the families of fallen comrades were leaving their wives to take up with WTC widows. The fire department says it knows of three such relationships, although media reports said as many as a dozen developed.

On New Year’s Eve, according to police and fire department accounts, firefighter Michael Silvestri left colleague Robert Walsh with severe facial injuries by hitting him with a metal chair after alcohol-fueled taunting about each other’s work habits and sexual orientation.

Colleagues tried to cover up the incident, telling doctors that Walsh had fallen down some stairs. The cover-up quickly fell apart, and all 50 members of the firehouse, nicknamed “Southern Comfort” for its southern Staten Island location and low number of fires, were reassigned to other companies within the department.

A captain involved in the incident was demoted and fined $90,000.

Fire Commissioner Nicholas Scoppetta has begun a crackdown on drinking, long an open secret in the tight-knit culture of the New York City firehouse.

On Jan. 18, fire department investigators raided the East Harlem home of Engine Company 53 and Ladder Company 43 and found beer and liquor inside a locker. The department tested the companies for drugs and alcohol and two firefighters’ samples showed up positive for cocaine.

“These are by and large isolated cases that do not reflect on the whole department,” department spokesman Frank Gribbon said. “There are more than 11,500 firefighters and fire officers who every day do an extraordinary job for the people … Ultimately that is the true public perception of what firefighters do.”