Fairfax County officials accused the District government yesterday of deliberately misleading them about Monday's riot at Lorton Reformatory in which 13 inmates were shot when D.C. corrections officers fired on prisoners with shotguns.

"The facts to me indicate that there was an intentional, systematic cover-up," Fairfax County Board Chairman John F. Herrity said. "They wanted to keep everybody in the dark and just live happily ever after."

Fairfax County, the District and the FBI have begun investigations into the riot and how it was handled, including whether notification procedures spelled out in a June agreement between the county and the D.C. government were followed.

Fairfax and D.C. police officials maintain that they were told on Monday only that a "peaceful demonstration" was under way at Lorton's Central facility and were not notified when the incident turned violent. A total of 17 inmates and two officers were wounded during the riot, a corrections official confirmed yesterday.

Corrections officers do not normally carry guns and Monday's incident marked the first time a weapon had been fired inside a Lorton facility since November 1968.

"We've tried to work cooperatively with the District," Herrity said, "but it seems like every time we do, they pull some bonehead manuever."

D.C. Corrections Director James Palmer said yesterday that the county was notified properly, but "if we did something wrong, we will rectify the matter." He stressed that at no time did any inmate "break the perimeter of the facility."

Herrity, a frequent critic of the District's prison, which is located in southern Fairfax County, said he has asked the county attorney to investigate the uprising and determine if there is a way to make the June notification pact legally binding.

The pact states that Fairfax police are to be alerted about escapes and disturbances immediately after Palmer is told. Herrity said he would like to see the District held in contempt of court if the county is not notified properly about incidents.

D.C. Mayor Marion Barry could not be reached for comment on the incident, a spokeswoman for his office said.

Palmer said that four inmates were treated for "pellet wounds" at D.C. General Hospital. He said one had been released and that the others were in stable condition yesterday. The other gunshot victims were treated at the prison's infirmary, he said.

The names of the injured inmates were not immediately available.

Herrity said Fairfax police were told about 3 p.m. Monday that there was a "peaceful demonstration" at the facility, and that at 7:30 p.m. the county was told that the situation was under control. Prison officials did not inform the county that there was a major disturbance with injuries, a police dispatcher said.

"I do know for a fact that the helicopter from the Fairfax County Police Department did circle the area, and I have been informed that at the time of the disturbance, a uniformed Fairfax County police officer was at the facility," Palmer said yesterday.

Corrections Department sources said that a Fairfax police helicopter circled the Central facility during a portion of the 5 1/2-hour standoff between inmates and officers that led up to the shootings, but the sources said that the helicopter apparently left the area before the shooting began.

In an interview with United Press International, Herrity also criticized D.C. City Administrator Thomas M. Downs, who earlier told The Washington Post that the incident was "a minor disturbance."

"That's like characterizing the Battle of Waterloo as a tea party of little old ladies," Herrity said.

T. Farrel Egge, the supervisor for the Mount Vernon District, where Lorton is located, said, "Here we have a facility that has historically not been a model facility. We thought we had worked out a minimum agreement for notification . . . but even that is not being honored."

The melee Monday came after corrections officials tried to transfer five inmates they believed to be the leaders of a three-week work stoppage by prisoners who work in the laundry, license plate, furniture repair and print shop of the Central facility. The institution houses medium-security inmates in dormitories.

When one of the inmates was taken into custody, Palmer said, about 300 other striking inmates gathered in the facility's quadrangle and demanded his release. He said the inmates were peaceful throughout the day, but that when they refused to return to their dormitories for the 4 p.m. head count, officers from Lorton's seven other facilities were called to Central, bringing to 250 the number of riot-equipped guards there.

Palmer said that tear gas was fired about 5 p.m. in an attempt to disperse the inmates, most of whom ran from the quadrangle, but that it was raining and the gas did not have much effect.

A short time later, Corrections spokesman LeRoy Anderson said, a small group of officers was spotted by the inmates, who, armed with bricks, homemade knives and other weapons, chased the officers into the quadrangle, where seven other officers were armed with shotguns.

According to Palmer, "When they charged the officers, the order came for the officers in front to hit the ground, and the other officers fired into the crowd." He said one warning shot was fired, followed by 23 shots into the group of rioting prisoners.

Anderson said that 13 prisoners suffered gunshot wounds, but no information about the injuries received by the other four inmates was available. One corrections officer was hit in the shoulder with a brick and another was overcome by tear gas, he said.

Palmer said that the situation at Central was calm yesterday, and that some of the 500 striking inmates who stopped work Sept. 9 to protest low pay and poor medical and food services had returned to their jobs.

He said the prisoners who did not return to work were told yesterday that they will be replaced, and that "we will take all the necessary sanctions to enforce the institution's rules," including the possibility of giving striking inmates an adverse recommendation when they come up for parole.

Palmer said his department's investigation of Monday's incident would also cover allegations made by an inmate in an interview yesterday with WDVM-TV (Channel 9) that two corrections officials were embezzling money from a Lorton work fund.

Elsie L. Munsell, U.S. attorney for the Eastern District of Virginia, said yesterday that her office has asked the FBI "as a precautionary measure to initiate a preliminary inquiry into the event at Lorton." Munsell and an FBI spokesman declined to say when their offices were informed of the shootings.

Corrections officers who patrol the cell blocks and grounds of the D.C. Jail and Lorton Reformatory are not armed with guns. The only officers with access to rifles, shotguns and handguns are those who man towers on the perimeters of the facilities.

Monday's incident was apparently the first time shotguns were taken into a Lorton facility since October 1980, when corrections officers armed with shotguns and firing mace stormed a building at Youth Center No. 2 to break up a fight between two inmate gangs.

The last time an inmate was shot inside a Lorton facility was in November 1968, when a corrections officer fired a handgun in a cell block and the bullet ricocheted off a ceiling and wounded an inmate in his cell.