A truck hauling 75 drums of toxic and flammable waste from a New Jersey chemical plant was stopped by Prince George's police Tuesday night after an officer noticed the chemicals were leaking on the Beltway near Ritchie Road.

Traffic was halted on the Beltway in both directions for 30 minutes as police and fire officials escorted the truck, which was operated by Plaza Freight Transport, of Fairlawn, N.J., to an empty parking lot of the nearby Capital Centre Arena.

Four policemen and one fireman were exposed to the chemicals while investigating the leak. They were examined and released from Prince George's General Hospital after complaining of eye irritation and shortness of breath.

According to state health officials, the leak posed no danger to surrounding areas.

"The only problem is that it emitted noxious fumes," said Jon C. Crosby, of the state office of environmental programs. "In a confined space and without artificial breathing equipment, you could die from this stuff."

The chemicals were phenol and toluene, byproducts of dyes manufactured at the Toms River, N.J., plant of the Ciba-Geigy Co., a major chemical and pharmaceutical manufacturer headquartered in Ardsley, N.Y.

Maryland health officials requested that Ciba-Geigy hire a Baltimore firm to clean up the trailer truck and spilled material and secure the leaking drums for transport back to the Ciba-Geigy plant. Crosby said the cleanup, which began yesterday morning, would take a day and would cost Ciba-Geigy a few thousand dollars.

Similar accidents occur three to four times a month in Maryland, Crosby said. Transportation of chemical wastes is covered under a 1977 federal law enforced by the state. The law requires certification of both the shipper and hauler of wastes, as well as proper labeling of the truck and its contents.

According to Ciba-Geigy spokesman Charles Keene, the Toms River plant and its contract hauler meet federal hazardous waste requirements.

"If all the regulations were obeyed, one wonders why these drums would have leaked," said Crosby, who said the incident is under investigation by state health and federal transportation officials.

The waste materials were bound for a Ciba-Geigy disposal plant in McIntosh, Ala. The shipment was one of four to five regularly scheduled disposals of the waste material, Keene said.