200 Evacuated in Costa Mesa Toxic Scare : Fire: Residents return--after more than two hours--when smoke escaping from a building being fumigated turns out to be harmless.

About 200 people in a city block between Harbor and Newport boulevards were evacuated for more than two hours Saturday morning after fire officials feared that smoke escaping from an apartment building being fumigated might be toxic.

After an investigation by hazardous-material response teams from Huntington Beach, Newport Beach, Costa Mesa, Santa Ana and the county, however, officials determined that no toxics were involved and residents were allowed to return home.

The problem was traced to a large gas water heater in the building at 399 Bay St., which was being fumigated by a termite control company.

“We think that the problem was a combination of the tent and the chemicals used in the fumigation,” Costa Mesa Fire Capt. Herb Ohde said. “Together they cut off the oxygen in the vent, where the gas lit the heater. It caused the gas to mix with dirty air. That created the white smoke.”

It took more than two hours to find the cause because the fumigation company had to return to remove its tent over the building, he said.

The smoke was first spotted about 8 a.m., leading to the evacuation of residents from three apartment complexes and a nearby trailer court, as well as from the Theodore Robins Ford dealership on Harbor Boulevard.

Ohde said two things kept the evacuation from being bigger than it was: The smoke blew toward the car dealership’s large, empty parking lot, instead of toward other residences, and many of the people who would have been evacuated were already gone because their homes were being fumigated anyway.

Ohde said the water heater problem burned a section of the tent about 3 feet by 3 feet.

No injuries were reported, but one woman suffering from emphysema who ran out in a panic was placed under temporary medical observation, he said.

Even though the problem turned out to be less serious than expected, the incident excited many residents whose morning routine was abruptly interrupted. Costa Mesa police officers went from apartment to apartment and to the nearby trailer court to ask residents to vacate the area.

Because the fumes were blowing west toward Harbor Boulevard, the police ordered residents to head toward Newport Boulevard.

Some residents said they were still asleep when police came knocking at the front door.

Others were in the middle of breakfast.

“I was drinking coffee when Costa Mesa police knocked on the door and said they were evacuating the place,” said Mike Sletten, 23, who lives in one of the apartment buildings.

“A policeman told me there were poison fumes in the air and we had to get out fast,” he said.