A disturbance among inmates broke out last night at the District's Lorton Reformatory in crowded Youth Center No. 2, one of the facilities to which prisoners were transferred after explosions earlier this week at another section of the reformatory.

There were no reports of injuries last night, and prison officials said the disturbance was quelled in about an hour.

Corrections officers, who illuminated the area with flares, fired tear gas to disperse the inmates, who did not clash physically but "argued verbally in a hostile manner," according to James Freeman, assistant director of the D.C. Department of Corrections.

The disturbance, which drew Fairfax County and Virginia State police to the prison, apparently stemmed from tensions generated by Thursday's transfer of 190 inmates from Youth Center No. 1 to already crowded Youth Center No. 2.

At the outset of last night's incident shortly before 9 p.m., about 100 Youth Center No. 2 inmates left their dormitories and raced to the facility's gymnasium, Freeman said.

Their aim, he said, was to express their annoyance at restrictions created by the housing in the gym of about 140 prisoners from Youth Center No. 1. Freeman said the transfer has reduced visiting hours at the youth center and has prevented use of the gym for recreation.

One man who lives near the prison said he saw inmates running across open space. Amid loud bangs, flares went into the air as the inmates ran, he said, and some of them started a brush fire.

Freeman reported no injuries. There were no reports of any weapons displayed or used by the inmates.

After the transfer of inmates within the reformatory on Thursday, the most severe crowding was reported at Youth Center No. 2, which housed its capacity of 250 inmates before the transfers.

"We are very, very concerned about all the institutions being so overcrowded," said a spokeswoman for the local union that represents D.C. corrections officers. Dorothy Donnelly, the spokeswoman, said crowding was a principal cause of last night's incident.

A source in the corrections department pointed to what he described as a traditional rivalry between inmates at the two youth centers.

After the incident last night, corrections officers began a shakedown of the youth center, aimed at determining whether any inmates had fled. Authorities set up a roadblock on Rte. 123 near the prison, and a helicopter hovered overhead.

By early this morning much of the tension appeared to have abated, and some of the Fairfax County police officers who had been posted at the prison's perimeter were being sent home. No escapes were reported.

In a separate matter, D.C. Department of Corrections officials confirmed that a bottle of special "invisible ink" used to mark the hands of visitors is among items missing from an armory at the reformatory's maximum-security facility.

Officials had previously said that four .38 caliber guns and 24 rounds of ammunition for the guns were the only items not accounted for after an inventory of the armory, located in the first level of guard tower six.

Officials from the union local that represents corrections department employes called the disappearance of the ink "a very severe" breach of security.

The ink is used at all six facilities in the sprawling southern Fairfax County complex to stamp the hands of visitors to prevent corrections officers from releasing inmates by accident.

In an interview yesterday afternoon, James Palmer, head of the D.C. Department of Corrections, said aides are conducting an internal investigation of the apparent thefts and that the FBI has undertaken a separate probe.

Palmer said the disappearance of the ink and stamp caused "serious problems" but that "we have changed our procedures" for stamping visitors' hands. He declined to elaborate.

Sources within the prison complex said they knew of no changes in the way visitors are stamped.

Earlier yesterday, D.C. and Fairfax County fire officials and an investigator from the D.C. Department of Occupational Safety and Health spent their second day drilling holes into the ground at Lorton's Youth Center No. 1 seeking the source of the methane gas blamed for the explosions.

The exact source of the gas has not been determined, but fire officials said the gas is probably seeping into the facility from a nearby landfill.

Anthony Johnson, 25, who was injured Thursday, remained in critical condition yesterday at the Washington Hospital Center. Arthur Moody, 26, who was burned in Monday's blast, was in serious condition at the same hospital, a spokeswoman said.

Johnson and Moody were housed in the same dormitory about six rooms away from each other. Both were smoking when the explosions occurred, and officials from Washington Gas Light Co. said that the blasts were fueled by methane gas.

Fairfax County officials, who frequently criticize the city's operation of Lorton, yesterday called for renewed negotiations between county and city officials over fire and rescue services. The two governments have been haggling for several months over who has the authority to provide fire protection to the prison.

Preliminary reports indicate that Fairfax County fire equipment was detained at the Lorton complex gates for almost an hour Thursday before being allowed to enter the compound, according to Board of Supervisors Chairman John F. Herrity.

"Maybe if the agreement was in place, this could have been avoided," said Herrity. "It possibly could have included inspections for things like a gas leak."

At a news conference yesterday, Palmer responded to Herrity's statement by saying, "I'm satisfied that all the people who were there cooperated with each other.

"I have no reason to believe that we would not let them county fire vehicles . . . come in," Palmer said. However, he said he "welcomed" Herrity's comments and was "amenable" to suggestions on improving communications between his department and the county.