A tentative, four-year agreement has been reached between the union representing nearly 9,000 Con Edison workers and the utility.

After 15 days and 20 hours of face-to-face negotiations that began on Tuesday, union bosses announced Wednesday morning that a deal had been reached on wages, health care and pension plans.

Utility Workers Union of America Local 1-2 spokesman Joe Flaherty told the media assembled on Hudson Street in lower Manhattan that Con Ed had come up significantly on wages. Also, traditional pension plans will not change.

Flaherty also thanked New York Governor David Paterson for sending a negotiations expert to help resolve the dispute.

The union had threatened to walk off the job early Sunday if an agreement wasn’t reached but Paterson, expressing concerning about the potential impact a strike would have on customers during hot weather, stepped in late Saturday.

Most of the union’s workers maintain the utility’s gas, electric and steam delivery systems for some three million customers in most of New York City and Westchester County.

The two sides didn’t agree on what effect a strike could have had, with Flaherty arguing that a walkout would be “catastrophic,” particularly for elderly and disabled customers. Con Edison, however, had insisted it could keep the power system running smoothly during a strike.

The utility had repeatedly pointed out that about half of its managers rose through its ranks and would respond to any emergencies if workers struck. However, non-emergency repairs and meter reading could be delayed, the utility had said.

In 1983, a strike by the union lasted more than two months. During that strike, a 20-block area including the garment district went dark for days after a water main break started an electrical fire in a substation. The blackout forced hundreds of offices and stores to close.

Gimbels and Macy’s department stores used emergency generators.

Crews of Con Ed supervisors worked to splice power lines to other substations and bypass the destroyed transformers. Con Edison officials at the time said the strike had no effect on the company’s response to the outage.

(Sources: MyFox / 1010WINS / WNBC)