Three explosions in a National Archives warehouse in Suitland yesterday destroyed or damaged 26 million feet of historic newsreel film, including film showing the bombing of Pearl Harbor, other World War II battle footage and scenes from the Depression.

The explosions and ensuing fire sent toxic gases billowing into the air and forced the evacuation of more than 100 persons from nearby apartments and businesses. Firemen battled the fire, which produced flames 20 to 30 feet high, for more than an hour before bringing it under control.

By that time, officials said, most of the newsreel film was probably destroyed. Fourteen firemen and three civilians and one policeman were injured, none of them critically.

The intense heat of the fire and the presence of hydrogen cyanide and sulfur dioxide, gases created by the burning of the nitrocellulose film, made the area hazardous for several hours and prevented firemen from entering the warehouse.

The fire is the second at the Suitland archives warehouse in a little more than a year. In August 1977, fire destroyed about 800,000 feet of film and was part of the reason for a June 1978 General Accounting Office report critical of the way the films were being stored.

Ironically, in a letter mailed yesterday morning, Rep. Richardson Preyer (D-N.C.), chairman of the House government information and individual rights subcommittee, asked GAO officials to hold furthr hearings on the situation next year.

Preyer's letter cited "disturbing reports... about the adequacy of the physical storage and preservation of documents and audiovisual materials at the National Archives and Records Service and its regional records centers."

Yesterday's fire broke out shortly after noon and was followed by the three explosions, which occurred several minutes apart.

"I've never seen anything like it in my life," said Prince George's County police officer Joseph Frohlich. "I saw smoke coming out of the building and called my dispatcher with a fire report.

"Then there was a boom! The firemen got here a minute later and started to go in. There was another boom! and they went flying back against the fence. It was incredible."

The third explosion sent several more firemen reeling as black smoke began shooting through the roof mixed with raging fire.

Officials on the scene agreed that the weather conditions prevented an even worse disaster. A westerly wind was blowing the fire away from nearby buildings and the day was dry -- water vapors, combined with the sulphur dioxide gas from the fire would have created a highly explosive mixture.

But the billowing smoke, which was mixed with toxic sulphur dioxide and hydrogen cyanide gases, caused extreme concern among fire officials who decided to evacuate the surrounding area.

That decision sent policemen and firemen, many of them wearing gas masks, running into nearby apartments and restaurants, to order people out.

"I thought it was some kind of SWAT team coming after a guy with a gun," said Ernestine Kornegay, who lives in the Arnold Garden apartments, about two blocks from the warehouse. "But when I opened the door all this smell came in and I couldn't breathe."

Others were amused by the situation, "People were just getting up and leaving their $5 and $10 lunches," said John Thomas, a bus bov in the Cedar Hill Inn, which is just down Suitland Road from the explosion site.

James Moore, director of the audio-visual division of the National Archives, said it is impossible to estimate the value of the destroyed film.

"There's no way to put an estimate on the film lost becuse its value was historical," Moore said. "It was film on file from 1929 through 1951. Much of it was out-takes of newsreels made during World War II and had never been seen by the public."

Moore and fire officials had no explanation for the explosions. Last year's fire was caused by a defective refrigeration system that allowed the temperature in one of the film vaults to go too high, causing spontaneous combustion.

That fire, however, was confined to one film vault because of a safety system designed to contain any fire to the vault it starts in. That system did not work yesterday, according to federal officials and at least 18 of the 27 vaults in the warehouse were destroyed.

Last year's fire was blamed on the "spontaneous combustibility of nitrate base film, excessive heat in the vault, and poor storage and handling practices," by a General Services Administration committee that studied it.

To put the fire out, firemen had to congregate at the left side of the building -- upwind -- and send water into the building through he burnt-out walls. Many wore gas masks. Others came out of the area coughing frequently.

"These gases are irritants both to the skin and lungs," fire Capt. Duncan Munro explained. "In an enclosed area they can be lethal. Even in the open they are dangerous. That's why we decided to evacuate the downwind area at least for a while."

Spectators clustered upwind of the warehouse to watch firemen, county police, security police from nearby Andrews Air Force Base and GSA and archives officials run back and forth as the fire continued. Many of those evacuated joined the crowd of about 150 spectators.

In all more than 60 firemen from seven engine companies and two truck companies, fought the fire.

The cause of the fire is under investigation by both GSA and the Prince George's County fire department.