For members of Connecticut's 142nd Medical Company of the National Guard, the most dangerous part of duty in the Persian Gulf was not enemy fire but a U.S.-made weapons system known in the field as "metal rain."

The weapons system -- small bomblets fired in clusters of 88 or more by artillery -- was responsible for two deaths and a half-dozen serious injuries in the unit.

Published reports say at least 19 U.S. soldiers -- about 10 percent of all those killed in the gulf -- were killed by cluster-type bomblets used by the Army and the Air Force. Hundreds of civilians also were killed or wounded by the bomblets.

Military officials say the victims themselves were to blame for many of the deaths: Unexploded bomblets were popular souvenirs, at least until they started blowing up in trucks and duffle bags.

But government documents and other sources point to other problems as well. The weapons, first developed in 1971, have a long history of problems which affect their use.

At least two of the Army plants that produce the bomblets or parts of the bomblets have been investigated for complaints that the manufacturing process was flawed; one is being shut down. Soldiers in the field say the weapons system that delivered millions of bomblets failed to perform at expected levels during the gulf war. And some say that the National Guard units that served in the war -- including the 142nd -- lacked specific training in handling the unexploded ordnance they found in the soft sands of the desert.

It is believed that unexploded ordnance picked up by members of the 142nd was responsible for the Feb. 28 explosion that killed Spec. Cindy Marie Beaudoin of Plainfield and Maj. Mark Connelly of Pennsylvania and injured three other soldiers, and the March 5 explosion that injured three more.

Defense department officials have said it is impossible to tell which of the three types of bomblets used by the Army -- the M42 and M46 types fired from howitzers and the M77s launched in rockets -- were involved in the two explosions, investigators say they were

Army bomblets.

"They know it's that type of bomblet. They're similar in design," said Ken Miller, a spokesman for the Army's Criminal Inivestigation Division. A completed Army investigation of the explosions is being reviewed and is expected to be released within the next few weeks.

The three types of Army bomblets are manufactured at seven munitions plants, most of which make only parts of the weapons.

From time to time over the past decade, the General Accounting Office has cited problems with the howitzer-launched weapons system and its manufacturers. More recently, complaints have surfaced over quality control at two plants that manufacture Army bomblets and the shells that deliver them.

A Mississippi plant, designed as a state-of-the-art producer of the howitzer munitions, is scheduled to be closed next year and workers are destroying 2.4 million defective bomblets produced there.

Because of production and quality-related problems, less than half of the bomblet-packed howitzer shells loaded, assembled and packed at the plant for a four-year period between 1984 and 1988 passed ballistics tests, the GAO reported. The plant produced 205,506 rounds and only 84,660 rounds, or 42.3 percent, had passed the tests.

The GAO said eight consecutive lots of shells produced at the plant from January through March 1988 failed ballistics tests because of split nose cones.

And, although it is a problem the Army says has been eliminated, one third of the shells produced between March 1986 and February 1987 had to be reworked because the fiberglass wrapping was separating from the projectile.

According to research done by the Army's Ballistic Research Laboratory, performance of the bomblets is affected by the rockets used to disperse them. The report, which does not identify vendors, said some had a high number of bomblets damaged during firing. The damage meant the bomblets often did not perform properly.

Robert Whistine, a spokesman for the Army's Ammunition and Chemical Command in Rock Island, Ill., said munitions from the Mississippi plant were sent to the gulf for use by U.S. forces during Operation Desert Storm. A former commander from the Mississippi facility assigned to the Persian Gulf theater identified them at the front, he said.

There is no evidence to suggest any of the rounds leaving plants for use were anything but quality ammunition, he said. He said the large number of faulty shells found at the Mississippi plant shows how closely the Army watches quality control of its munitions.

A second munitions factory in California was investigated by the Army Inspector General in 1989 after a plant inspector claimed the Army's contractor was producing cracked and inferior quality M42, M46 and M77 bomblets. The plant's contractor is NI Industries, formerly known as Norris Industries Inc., which produces the casings for the bomblets. A company spokesman did not respond to four requests for comment.

The Army Inspector General eventually concluded after two inquiries that the charges were unsubstantiated.

However, the whiste-blower, Roger Kiser, a former plant inspector, has been circulating his complaints alive for more than

two years. Kiser collected taped testimony of fellow plant workers who also acknowledged quality control, production and pollution problems at the plant now earmarked for a superfund chemical cleanup.

NBC's Expose television show and a local newspaper, the Riverbank (Calif.) News, carried accounts of Kiser's complaints, and he recently filed a $100 million federal lawsuit asking the government to destroy munitions produced at the California plant and for NI Industries and the Army to repay taxpayers for funding the munitions program.

Whistine said there was nothing wrong with the munitions produced. In fact he said that only five out of 47 million rounds checked over several years by Army quality control personnel showed any defects at all.

However, one NI Industries report signed by an Army quality assurance representative on Aug. 8, 1989 indicates that about 115,000 M42 grenades had problems with nicks and burrs incurred on the California production line.

After the NBC report, the Army did a test of two lots of 66mm mortar rounds produced under Kiser's supervision and found 100 percent of the munitions passed the test, according to Maj. Rick Thomas, an Army spokesman. The Army did not test any other munitions from the California plant, he said, because Kiser said he was talking about munitions produced on his production line at the plant.

Because it is extremely time-consuming to check lot numbers, Whistine said the Army would have to charge the media hundreds of dollars to discover whether rounds from the California plant were used in the gulf. There was no need for the Army itself to check, because the Army Inspector General cleared the contractor of wrongdoing.