WOODBRIDGE >> A four-alarm fire that caused extensive damage to the Jewish Community Center of Greater New Haven and injured two firefighters has been ruled accidental in an initial investigation.

The probe into the cause is continuing, according to a Fire Department post on Facebook. The JCC may stay closed for six to 12 months, JCC Chief Executive Officer Judy Diamondstein has said.

Many of the JCC’s daily activities, such as pre-kindergarten and sports, are continuing in other locations.

The department has said the fire was not arson.

“With the assistance of the Department of Public Protection Fire and Explosive Investigation Unit and one of their State Police Detectives with an Accelerant Detection K-9, we have ruled out an intentional fire,” the department’s post said.

“While the investigation is ongoing, we believe the fire started in the sauna area located in the men’s locker room,” it said.

The department asks anyone with information to contact Fire Marshal Joseph Cappucci at 203-389-3445 or jcappucci@woodbridgefire.com. The Dec. 5 blaze at the JCC, 360 Amity Road, started around 3:30 p.m. in the area of the locker rooms and men’s sauna.

The staff evacuated about 300 people from the building. The two injured firefighters are expected to make a full recovery.

Diamondstein said there was extensive water and smoke damage and some of the basic work to restore the facility can’t begin until March. The JCC has “a very special community” that is understanding of the situation, she said.

The 100,000-square-foot building has about two miles of ducts that need cleaning, Diamondstein said. The lower level of the building had about 6-8 inches of water once the fire was out and the new basketball court and the aerobics studio were ruined.

The building “isn’t safe” to be occupied, so in addition to relocating activities, the offices are moving, she said.

“It’s a mammoth, mammoth job here,” she said. “It’s going to take a village.”

Some 77 pre-kindergarten students and 40 in an after-school program have been moved to Congregation B’Nai Jacob.

Officials say they are close to settling on a location in town for the fitness center, have moved the basketball program to Hopkins and Beecher Road schools, swim lessons to the Orange Community Center pool and racquetball to Quinnipiac University.