A section of Maryland Rte. 48 was shut down near Frostburg, Md., yesterday after a highly toxic chemical leaked from a ruptured drum being carried on a tractor-trailer truck, state police reported.

About 10 persons were evacuated from homes in the area but there were no immediate reports of injury or illness.

Police said the eastbound truck was stopped by a trooper near the border between Garrett and Allegany counties about 6 p.m. They said toluene di-isocyanate, which they described as a cancer-causing chemical, was leaking from at least one of 74 drums on the truck. Inhalation of fumes could be fatal, police said.

According to police, they began searching for the truck after receiving a report that it appeared to be leaking fuel.

They said they believed that the chemical had been leaking over a stretch of about 15 miles of road. The chemical is used in the manufacture of polyurethane.

About 10 persons living near the affected area were evacuated while a hazardous materials unit was summoned from the state fire marshal's office in Baltimore to assess the danger and supervise the cleanup.

Traffic was rerouted from a five-mile section of the road near Big Savage Mountain.