MALDEN, W.Va. (AP) _ Authorities working to halt a leak that earlier forced the shutdown of five schools evacuated 4,000 homes today so they could try to transfer the corrosive and volatile chemical from a tank to a truck.

''This chemical is so corrosive you can't put it in a standard tank as we know it,'' said Lt. Larry Mullins of the Kanawha County Sheriff's Department.

''We're evacuating as a precaution. Better safe than sorry.''

The 4,000 houses near the J.Q. Dickinson and Co. plant are in the Kanawha City section of Charleston, Malden and Rand. An initital statement said Marmet was included in the evacuation zone, but Mullins said it only extended to Marmet city limits. Mullins said residents were being moved to a temporary shelter at a high school.

The foul-smelling chemical, liquid bromine, is volatile when it comes in contact with moisture, Mullins said.

''We wouldn't dare attempt a transfer until everyone who wants to get out can get out,'' he said.

''If the tank ruptures there could be a cloud which could be hazardous to the community,'' said Libby Squire, spokeswoman for the County Commission.

The houses were to remain evacuated until afternoon, when the transfer was to be finished, said Charleston police Cpl. Dallas Staples.

Bromine began leaking Wednesday from a 4,000-gallon tank at the plant, said plant manager Roger Hovey. Bromine is used in the manufacture of photographic materials and dye.

Classes at five schools were canceled today, and one person suffered eye burns Wednesday when the leak began.

Malden Fire Chief J.D. Waggoner said today that bromine continued to leak from around a patch placed over a hole in the leaking storage tank.

A tank truck was on the scene today, but officials couldn't decide the safest way to transfer the chemical to the tanker, Waggoner said.

Waggoner said officials were still searching for a specially designed pump to transfer the chemical. If the transfer is made, the truck would return the bromine to its manufacturer in El Dorado, Ark., Hovey said.

Officials said the evacuations were prompted by worries of a worse leak during the transfer.

Waggoner said the tank was about three-quarters full when the leak began, and about 2,000 gallons remained this morning. He also said that if officials could not find a pump, the bromine would be drained on the ground and neutralized.

On Wednesday, attempts by plant workers to seal the cylinder with a ''belly band'' failed, said sheriff's Lt. D.E. Drennen. He described the hole in the tank as a ''pinhole.''

Some of the chemical got into a worker's eyes, which were flushed with water and treated at the scene, emergency officials said.

Mike Bell, a spokesman for the Kanawha County Board of Education, said county officials agreed with emergency workers who suggested that classes be canceled at five schools because of the leak.

The chemical, used in making photographic materials and dyes, has an unpleasant odor and irritates mucous membranes, Hovey said.

''We all started coughing and wheezing a little bit at first,'' Hovey said.

The chemical plant is two miles southeast of Charleston and one of several that line the Kanawha River in central West Virginia. The ''chemical valley'' was the scene of a series of leaks in August and September, the worst of which was a Union Carbide leak at Institute on Aug. 11 that sent 135 people to hospitals.