SALT LAKE CITY (AP) _ A man arrested after agents discovered 93 homemade pipe bombs and the materials to make hundreds more at his house was arraigned today on federal firearms charges.

Neil Baker Jr., 37, appeared before U.S. Magistrate Calvin Gould, who scheduled detention and preliminary hearings Tuesday and ordered Baker to remain in the custody of U.S. marshals meanwhile.

Baker is charged with two counts of illegal possession of firearms, which carry a maximum penalty of up to 10 years in prison and a $250,000 fine.

Jerry Miller, agent in charge of the federal Bureau of Alcohol, Tobacco and Firearms in Salt Lake City, said Baker was arrested at his home on the city's west side during a raid Wednesday.

Miller described the house as a ''clandestine explosive device manufacturing plant.'' He said some bombs made there had been sold, but none had been used in the area.

Police Lt. Jim Bell said the raid followed a joint investigation between his department and the federal agency. He said a federal search warrant was obtained after ''we received some information that (someone) at this residence was manufacturing homemade pipe bombs.''

Miller said he did not know how or to whom the bombs were to be distributed or if other people were involved, but that the investigation was continuing. ''There are some people we want to interview,'' he said.

Two other people were in the house when it was raided, but both were released after questioning, Miller said.

Asked if there was any link between the bomb-making operation and three bombings in Coeur d'Alene, Idaho, on Sept. 29, Miller said, ''As far as our investigation, there's no connection at all. But it's something we're looking at very seriously.''

The bombs were of two types: galvanized steel pipes and cardboard cylinders. Both types were equipped with fuses and appeared to contain black powder, screws and other shrapnel-like materials, Miller said.

''They are used to destroy property and take human life,'' he said, adding that a blast would kill or maim anyone nearby.

He said the materials used in the bombs were commonly available.

Demolition experts from the Army's ordnance unit at Fort Douglas removed the bombs, which were taken to secure bunkers well away from populated areas, Bell said.

It was exactly one year ago Wednesday that two separate explosions of homemade bombs in the Salt Lake area killed Steven F. Christensen, 31, and Kathleen Sheets, 50.

The following day, a third device blew rare documents dealer Mark Hofmann from his car, seriously injuring him.

Hofmann later was charged with two counts of first-degree murder and 28 other counts of bomb-making, fraud and theft by deception. He remains free on bail while he awaiting his first trial, on the homicide and bomb-making counts, scheduled for March 2.

It was coincidence that the raid came on the anniversary of the bombings, Miller said.

''It wasn't planned. We just didn't want to leave these things on the street.''