The two methane gas explosions at the Lorton Reformatory last week provided a grim and perhaps fitting symbol for the District's chronically overcrowded and troubled corrections system.

Despite longstanding complaints from Congress and scores of lawsuits seeking improvements in living conditions for inmates, the D.C. corrections system continues to operate at or near the flash point -- with prisoners precariously stacked and shuttled back and forth between the prison and the D.C. Jail and no prospects for a long-term solution.

At the heart of the problem is a major philosophical dispute between Mayor Marion Barry, who strongly opposes building additional facilities, and a criminal justice system and an irate public that appear determined to send more and more convicted criminals to jail for longer periods of time.

Barry contends that building more costly jails is not the answer, and that in the long run a projected decline in the prison population and increased reliance on halfway houses, social programs and other alternatives to incarceration will quell the problem. But the mayor's critics say they are fast losing patience.

"If they don't do something, Congress is going to ram something down their throat," said one well-placed congressional staff aide who helps oversee District affairs.

At 4 a.m. yesterday, the combined prison population at the D.C. Jail and Lorton exceeded the total capacity of the two facilities by 935, and by last night, with the return to the facilities of inmates making court appearances, on work release or from other approved absences, the total capacity was exceeded by more than 1,250.

The gas explosions last Monday and Thursday at Lorton's Youth Center No. 1, in which two inmates were seriously burned, touched off the latest crisis. Nearly 400 prisoners were evacuated from the dormitories and forced to double up elsewhere in the already crowded prison in southern Fairfax County.

Corrections officers used tear gas to quell a disturbance at the prison Friday night caused by the serious crowding and dealt with further unrest over the weekend. Two fires were set by inmates on Saturday night and Sunday afternoon and there were at least three reported attacks on corrections officers, according to officials of Local 1550 of the American Federation of Government Employees (AFGE), which represents the corrections officers.

Moreover, there have been growing conflicts among the 247 prisoners at Youth Center No. 2 and the 188 inmates who were transferred there from Youth Center No. 1, according to corrections officials.

In addition to a traditional rivalry between the two youth centers, many of the youthful inmates are under so-called "separation orders," meaning that they are not supposed to be housed at the same institutiion as certain other inmates because of personal conflicts. Officials are concerned about the possibility of violence growing out of the settling of old scores.

"It's a time bomb," said a corrections officer assigned to Youth Center No. 2. "I've been there several years and we don't have any control over what happens. The only control we have is to keep them from crossing the fence line."

Dorothy Donnelly, a staff assistant for Local 1550, also expressed concern for the safety of more than 50 prisoners in protective custody who are being housed in the library of Youth Center No. 2.

According to a corrections officer who declined to be identified, there have been two attempts to break into the protective custody area, which houses "snitches," homosexuals and other inmates who need to be segregated from the general prison population for their own safety.

The crowding at the facility also has meant that some inmate privileges have had to be scaled back, including visiting hours, which prompted Friday night's disturbance, according to prison officials. In that incident, a group of about 100 inmates from Youth Center No. 2 tried to break into a gymnasium housing 140 prisoners from the other facility in order to "rumble," according to a source in the corrections department.

Corrections Director James Palmer said in an interview yesterday that the city could not be blamed for the latest crisis, which apparently was triggered when cigarettes ignited methane gas apparently seeping from a nearby landfill that is operated by Fairfax County.

"If the proper people who have the responsibility would find the source to control the gas, I could send them the displaced inmates back in," Palmer said. " . . . Whatever the problem is is one that we have no control over. If it was, I could fix it."

Palmer said he plans to present City Administrator Thomas Downs with a "contingency plan" today for relieving crowding at Youth Center No. 2 "on a temporary basis." He declined to provide details of the plan, but said it does not include the early release of any prisoners.

He also specifically ruled out, for the time being, asking for relief from the Federal Bureau of Prisons.

"The Federal Bureau of Prisons is already 30 percent overcrowded," he said. "If I ship them away, I have to go to the trouble of shipping them back at tremendous cost. I can't pull money out of nowhere."

The city has been trying for years to deal with prison overcrowding, which has been the subject of a number of court suits.

U.S. District Court Judge William B. Bryant held Barry and other city officials in contempt in September 1983 for failing to reduce overcrowding at the D.C. Jail. Barry acknowledged at a news conference last month that the city still is not in compliance.

"We're doing all we can," said Barry, who left last Saturday on a trip to Africa. "I think we're on top of it. We have not had any serious disorders. We have not had any escapes of any serious consequences."

Barry contends that the District, with a population of 623,000, already has the highest per capita rate of incarceration of any city in the country. And when it comes to the issue of overcrowding, the numbers clearly tell the story.

The six-prison complex at Lorton was built to hold a maximum of 3,503 convicted inmates and the D.C. Jail was built to hold a maximum of 1,378 persons awaiting trial or already convicted -- a total of 4,881.

At 4 a.m. yesterday, according to department figures, the prison and the jail were holding a total of 5,816 inmates, or 935 more than the facilities were designed to hold. By 6 last night, the inmate population had risen to 6,131, Palmer said.

One of the biggest problems at Lorton, according to Professor Robert Johnson of the American University School of Justice, is that a large number of "confirmed criminals" are kept in dormitories instead of individual cells.

"There is no sense of privacy for the inmate to carve out a life for himself," Johnson said yesterday. "The dormitory is louder, there is uncontrolled movement and the inmates are always exposed to risk . . . . There is the potential for a jungle underground," which also increases the burden on corrections officers, he said.

The constant shifting of prisoners between Lorton and the jail -- a sort of sleight of hand effort by the city to handle the chronic overcrowding -- has at times defused legal and political problems but has done nothing to deal with the long-term problem.

A D.C. voter-approved determinant sentencing law, which was designed to insure that certain types of convicted criminals will serve specified prison sentences, also is expected to substantially add to the burden of the city's corrections system.

D.C. City Council member H.R. Crawford (D-Ward 7), who has proposed the creation of a blue-ribbon panel to design a new jail and choose a site for it, said yesterday that the city has no choice but to expand its facilities, regardless of the cost.

Crawford also said that the District owes it to suburban Fairfax County to take action to reduce the possibility of further violence or problems at Lorton.

The Fairfax County Board of Supervisors, citing the past week's violence at Lorton, voted unanimously yesterday to ask D.C. officials to discuss immediate plans for reducing crowding at the prison.

Sen. Arlen Specter (R-Pa.), chairman of the Appropriations subcommittee on the District of Columbia, also has discussed the possibility of building additional prison facilities on federal property, including the grounds of St. Elizabeths mental hospital and Bolling Air Force Base. But nothing has come of that idea.

"You can build more prisons, but is that the answer?" asked Hugh (Rusty) Hassan, the current head of union local that represents corrections officers. "We need more officers, better training, updated facilities and equipment . . . . It's a big problem that society doesn't want to deal with. Our corrections officers are doing a masterful job under very adverse conditions."

While Barry says he is philosophically opposed to building more prison cells, finances also are a big factor in the city's decision.

The city spends more than $100 million a year on corrections, including about $25 million paid to the Federal Bureau of Prisons for imprisoning convicted D.C. residents.

City officials estimate it would cost about $45,000 per bed to construct a new correctional facility and $42 a day to cover the cost of housing each additional prisoner.

"I'm hard pressed to believe we're not locking up enough people," said D.C. Budget Director Betsy Reveal. " . . . We really don't do enough about [prisoner] diversion."

Palmer said yesterday that a new center will be opened at Lorton in January or February that will add 400 beds to the prison, but that no other construction is planned.

Meanwhile, there is no telling how long it will take for city officials to determine the precise nature of the two explosions and take action so that the evacuated prisoners can return to Youth Center No. 1.

According to a number of geochemists, engineers and other experts, if methane gas is coming from the 300-acre landfill 700 feet east of the dormitory, it could take three to six months to design and install a system to keep the gas from migrating underground into the prison.

"Three to six months would be a disaster, as far as I'm concerned," Palmer said.