About 90 persons were examined at hospitals yesterday for possible exposure to toxic fumes after a two-alarm fire destroyed a warehouse in Gaithersburg where insecticides were stored, authorities reported.

No serious injuries were reported as a result of the fire, which was reported about 1:15 p.m. at the warehouse of Justin Gardens, Inc., at 19425 Laytonsville Rd.

Almost all of those brought to hospitals has been released by last night, some of them after receiving treatment for such symptoms as watery eyes, dry throats and anusea, hospital officials said.

Most of those taken to the four hospitals in Montgomery County were firefighters, but some were policemen, bystanders, and neighbors.

Persons living in the immediate vicinity of the warehouse were evaculated, said assistant Montgomery County fire chief Walter A. Wise.

However, he noted that the site is in a sparsely populated section of upper Montgomery County and said he believed the evacuation involved fewer than 10 homes.

He said it was not immediately known when those evacuated would be permitted to return to their homes.

Laytonsville Road was closed to traffic in the vicinity of the fire last night, and firemen remained on the scene attempting to continue the runoff from water that had been used to combat the blaze.

Wise said the purpose was to prevent the spread of potentially harmful residues of pesticides that had been stored in the warehouse. The residues were possibly dissolved in the runoff, he said.

A full inventory of types and amounts of pesticides could not be immediately obtained last night. However, one of them was believed to be Malthion, said Dr. John Rogers, the county medical examiner, who was involved with the fire as a volunteer firefighter. Malthion is often used by home gardeners, but can be toxic if ingested in high enough doses, he said.

He said that most of the firemen were sent to hospitals as a precaution.

"Everybody's apparently doing okay," he added.

About 30 persons were taken to Holy Cross Hospital, where it was anticipated that none would require admission. Suburban Hospital authorities said 26 of 29 persons brought there had been treated and released by about 6 p.m. The others were expected to be released shortly afterward.

Nineteen persons were brought to Washington Adventist hospital and released after showering and undergoing observation. Fifteen persons were examined at Montgomery General Hospital and released.

The cause of the fire was not immediately known last night. Chief Wise said an investigation had not been completed.

He estimated that about 70 firefighters were involved in battling the blaze, which was brought under control about 2:30 p.m.

Although he could not specify the dollar amount of the damage to the warehouse and its contents, he described the warehouse as being destroyed.

Mrs. Ray Gustin III, of Laytonsville, whose husband was the proprietor of Gustin Gardins, Inc., owner of the warehouse, said in a telephone interview that her husband was being examined at Holy Cross hospital last night as a result of his possible exposure to the smoke and fumes.

She said both fertilizers and insecticides were stored in the building for use in the company's commercial and residential landscaping business.

Among other jobs, she said, the company did the landscaping for the Lyndon B. Johnson memorial on Columbia Island.