A man described by police as a recent escapee from Spring Grove State Hospital led more than 20 police cruisers on an hour-long, four-county chase in suburban Maryland early yesterday in a stolen Dodge camper, police said. They said seven cruisers were wrecked, 20 other vehicles were forced off the roads and two officers were sent to the hospital.

A suspect, identified as Albert George Schaab, 19, of Laurel, was arrested after an officer shot the left tires of the camper, flipping it and injuring the man slightly. He was charged with three counts of assault to commit murder against police officers, auto theft, and several other offenses.

Schaab had escaped July 8 after one day at Spring Grove in Baltimore County, where he was sent for psychiatric evaluation after being charged with stealing emergency equipment, including sirens and red lights, from four Prince George's County police cars, police said.

During yesterday's zigzag chase, which reached speeds of 80 miles an hour and involved U.S. Park Police and officers from Prince George's and Montgomery counties, the driver was able to elude capture in part by monitoring his pursuers' plans on the police channel of the camper's radio, said Sgt. Anthony Amoia, the Prince George's officer who first spotted the Dodge.

The man broke in on the channel, swore at the officers and threatened to force them off the road if they tried anything, a police spokesman said. Meanwhile, the camper was scattering cars in its path, at one point speeding north on the southbound lane of Rte. I-95, police allege. One officer said the camper looked "like a huge tank coming down the road."

Police gave this account of the alleged incidents:

The chase began at 2 a.m. when Amoia saw the Dodge being driven onto the Contee Stone and Gravel Co. property in the 5600 block of Van Dusen Road in Beltsville. Amoia said that after he spotted the camper, the driver put it into reverse in an apparent attempt to hit the cruiser. But Amoia swerved into a ditch.

The camper raced onto Rte. 198 through Laurel and then onto the Baltimore-Washington Parkway, where two U.S. Park police officers tried to block the road by driving their cruisers slowly in tandem. But police said the camper hit the cars, slightly injuring the officers.

One, Sgt. James Chaconas, 38, was in satisfactory condition at Greater Laurel-Beltsville Hospital and the other, Officer Bernard Stasulli, 38, was treated and released for minor bruises.

From the parkway, police pursued the camper through the Department of Agriculture Research Center in Beltsville and then back to Contee Road and to Rte. 198. Prince George's police spokesman Bob Law said that at that point, the driver tried unsuccessfully to force a police cruiser into an oncoming tractor trailer.

The camper, which had earlier been driven briefly into Anne Arundel County, was driven back to Prince George's, then to Howard County and on to Rte. 29 in Montgomery, where it crashed through two police cars used as a roadblock.

Montgomery Sgt. Charles Lake said he decided then that "it was time to bring this chase to an end" and blew out the camper's two left tires with his .12-gauge shotgun. Schaab was treated and released at Holy Cross Hospital for lacerations to his face and head and bruises on his back. The camper, which police said had been stolen from 11700 Columbia Pike, Silver Spring, Tuesday night, was hauled away on a flatbed trailer.

In addition to the Prince George's assault and auto theft charges, Schaab was charged with three counts of assault with intent to commit murder against police officers. In addition, he was charged by Montgomery County police with auto theft, two counts of property destruction and seven outstanding traffic warrants. Park police charges were pending.

Schaab was being held at the Prince George's detention center on $100,000 bond. Police said they did not expect that he would be returned to the hospital.