ERIDIAN, Miss., July 8 — An assembly-line worker who had talked openly about shooting people walked out of an ethics and sensitivity training session at his factory this morning, returned moments later with a semiautomatic rifle and a shotgun, and opened fire, killing five co-workers before fatally shooting himself, the authorities and witnesses said.
Dozens of workers at the Lockheed Martin aircraft parts plant ran screaming from the cavernous hilltop building near here as the gunman, dressed in his usual black T-shirt and camouflage pants, but now wearing bandoliers full of extra shotgun shells slung across his chest, suddenly started blasting away at about 9:40 a.m.
When the police arrived minutes later, nine people had been wounded, one critically, in what was the nation's deadliest plant shooting in two and a half years.
The gunman, identified as Doug Williams, 48, of Meridian, was an assembler at the factory, which builds parts for the C-130J Hercules and vertical stabilizers for F-22 Raptor jets. He had worked there since 1984.
Brenda Dubose, who was hit in the face and hand, possibly by ricochet, had been sitting at one of three tables in an annex of the factory used for the sensitivity sessions. She said she did not notice Mr. Williams leave the room. But she did not miss him when he reappeared in the doorway, a shotgun on his shoulder.

"He was trying to shoot Steve Cobb, the plant manager, and the production manager, Jack Johns," Ms. Dubose said. Mr. Cobb was wounded; Mr. Johns was not.

Using an expletive, Mr. Williams barked, "What did I tell you all" about bothering me, Ms. Dubose said. "And everybody started hitting the floor, and he was just shooting.

"The bullets hit Micky Fitzgerald in the face," she continued. "Pellets hit the side of my face. I fell on the floor. I reached my hand up to feel it — he was still shooting people on the other side of the room — and it felt like there was a hole in my forehead, but there was only cuts and blood, from the pellets or whatever it was.

"I tried to see about Micky but his face was all shot up. I was moving around under the tables and he said, `I'm not going to shoot you, Bren.' "

Besidesthe 12-gauge shotgun Mr. Williams used, the extra shells and a Mini-14 .223 semiautomatic that he carried but apparently did not fire, the authorities said Mr. Williams's vehicle was stocked with a .22 Magnum derringer, a .45-caliber Ruger pistol, a .22 rifle with a scope and a large amount of ammunition.
Co-workers and others said Mr. Williams, who was white, was known as a racist for complaining about blacks and talking about shooting them. Four of those killed were black, and one was white.
One of those killed, Lynette McCall, 47, a black woman who had worked at the plant for 19 years, had told her husband of several disturbing incidents involving Mr. Williams, the most recent less than a year ago.
"That's what she told me," said her distraught husband, Bobby McCall. "He said he was going to come in one day and kill up a bunch of niggers and then he was going to turn the gun on himself."
Besides Ms. McCall and Mr. Fitzgerald, 45, the dead were identified as Sam Cockrell, 46, Thomas Willis, 57, and Charlie Miller, 58.
Officials said it was not clear that the shooting had been racially motivated. Sheriff Billy Sollie of Lauderdale County said it appeared that Mr. Williams had fired at random, and noted that the wounded included four blacks and five whites. "There was no indication it involved race or gender as far as his targets were concerned," the sheriff said.
Other workers described Mr. Williams as someone with a lit fuse, but whose anger was not necessarily — or only — directed at blacks.
"I'm thinking it was just whoever he was angry at," said Ms. Dubose. "He talked about `I'll kill somebody.' He talked about it, but I never did think he would do it."
Jarvis Towner, a co-worker who was not hurt, said Mr. Williams had made threats for years. "He's one of those people that if you figured someone was going to, you know what they say — `go postal' — it would be him," Mr. Towner said. "He was one of those kind of people. Most everybody has said that about him."
Mr. Towner added: "But to say that and really believe it is two different things."
Dain Hancock, the president of the Lockheed Martin Aeronautics Company, refused to disclose tonight whether company officials were aware of problems or complaints about Mr. Williams involving racism or potential violence. Sheriff Sollie said he had not yet reviewed Mr. Williams's personnel file. He added that Mr. Williams appeared to have had no criminal record.
Jim Kuykendall, the president of the machinists' union local, said the annual ethics class Mr. Williams had been attending covered a range of subjects in an hour and a half: "Everything from if there was a problem on the plane you're working on, would you confront your supervisors, to sexual harassment, to ethnicity," he said. The training emphasizes "how to get along together and respect each other," he said.
Janice Jenkins, a senior shop steward, said Mr. Williams, who was a divorced father of two, had gotten into a dispute with supervisors at the plant this morning when he and his girlfriend, Shirley J. Price, arrived and tried to punch in at a different spot than usual. But his girlfriend complained about the situation, not Mr. Williams, Ms. Jenkins said.
Ms. Jenkins said she had just returned to her work area, assembling C-130's, after a break when she heard "these loud booms" and thought they were electrical problems from some new wiring being done. Then she heard screaming and hollering: "Get out! Get out!"
Taking cover behind the factory's water towers, she helped a man shot in the arm, then left him when the shooting stopped. "I went around the corner and I was just, where is the guy, and where is the gun, and they're saying he's shot himself, he's dead, laying there," she said.
Ms. Jenkins went back to try to help the injured, but saw only a panorama of carnage.
"Horrible," she said. "That's the only word I can come up with. I can't believe something like this would happen."
Sheriff Sollie said Meridian had been through an extraordinarily difficult year already. "This year, Lauderdale County has had two 100-year floods," he said. "You're supposed to have one of those every 100 years.
"This," he added, "is not supposed to happen in your lifetime."
Mr. Towner, an assembler of C-130's, said the plant, which opened in 1969 and had 138 employees on duty this morning, had always seemed a friendly place. "It's really close, like a family," he said. "I think that's what makes it so hard. Even though he did it, he was one of the family. But he took away part of the family."