Lunchgoers at the Greenhouse Café on Monday afternoon had to seek alternative dining options after smoke from a fan's electrical motor closed the Science Center restaurant for the day.

Greenhouse employees noticed a smoky odor coming from the back of the kitchen late Monday morning and called the Cambridge Fire Department. Units responded and discovered that one of the kitchen's ceiling fans had burned out.

None of the café employees nor any of the 35 to 50 students seated nearby at the time were injured, but authorities shut down the entire area at 11:15 a.m., said Cheryl Y. Walker, assistant director for Campus Restaurants for Harvard University Dining Services.

Walker said the fan's motor was not defective, but that it burned out "due to normal wear."

Walker said the fan was replaced on Monday night, but it will not be functional until the ceiling motor is repaired tomorrow.

All other ceiling units will also be checked at the time.

The Greenhouse reopened as usual at 6:30 a.m. on Tuesday, but with a set of exterior fans flanking the restaurant's seating area to cool off customers.

In the meantime, Greenhouse employees are bearing the brunt of the missing fan.

"We're sweating like crazy, with the 80 degrees outside and the 500-degree oven," said Bob MacLaughlin, a Greenhouse pizza maker.