The two-alarm blaze broke out at about 3:30 p.m. The Annapolis Fire Department arrived on the scene and found heavy smoke and called the second alarm soon after the first, officials said.

It took about a half an hour and 30 firefighters from Annapolis and Anne Arundel County to get the fire under control.

Traffic on West Street was diverted, causing a major headache for afternoon commuters.

The blaze is under investigation, said Capt. Ed Hadaway, a city Fire Department spokesman.

It appears to have started in a first-floor bathroom and spread into the areas between the ceiling and walls. It appears to be an accident at this point, he said.

The blaze caused $300,000 in damages.

Employees in the front of the building saw the smoke and yelled to people in the back.

"It was bad," said employee David Glover of Arnold. "They think it came from the air conditioner on top of the building."

Mr. Glover said some people panicked at the smoke, leaving purses and car keys behind.

Others weren't so excited.

"We thought they were joking. We didn't see any smoke," said employee Tom Polidore of Glen Burnie.

Once they got outside, they saw smoke pouring out of the top and side of the building, and firefighters had to break some windows to control the flames.

Mr. Polidore said the business had a smaller fire in the other showroom last year, but it was only a problem with the air conditioner.

"It was nothing like this," he said.

West Street was closed from Admiral Drive to South Southwood Avenue until about 5 p.m., snarling traffic on the major thoroughfare.