One of three men charged with conspiracy in the bombings of eight abortion clinics and related facilities was released on $250,000 bond today over protests by federal prosecutors that the man is a danger to the community.

U.S. Magistrate Paul M. Rosenberg rejected prosecution pleas that Michael Donald Bray, 32, of Bowie, be held without bond pending trial. But Rosenberg imposed an unusual nighttime curfew on Bray and ordered him not to go within one mile of any abortion clinic or abortion advocacy center.

Sighs of relief came from Bray's family, and many of the approximately 50 supporters who filled the small federal courtroom here, when Rosenberg announced Bray's release after a 3 1/2 hour hearing. Bray, in jail since his arrest Saturday, embraced his wife Jayne, 29, his brother, Joseph Daniel, and his parents, Joseph and Beverly Bray, of Davidsonville.

Two other men arrested in the bombings, Thomas E. Spinks, 37, of Bowie, and Kenneth William Shields, 34, of Laurel, have been held without bond by magistrates in Hyattsville and Alexandria, at least for the time being.

The three men, described by prosecutors as fervently religious foes of abortion, were arrested Saturday in connection with the eight bombings, most of them in Washington and suburban Maryland, since last February. Federal Alcohol, Tobacco and Firearms Bureau agents seized what they said was a large quantity of explosives at Spinks' home, plus a notebook, maps and other papers they said linked Bray and Shields to Spinks.

In a new development, ATF agent John R. Schworm said at today's bail hearing that agents late Tuesday night seized another 200 to 300 pounds of chemicals, 20 compressed air cylinders, timers, fuses and other materials from an Anne Arundel County warehouse shed rented by Spinks under the name "Lou Burns." He said the materials were similar to those discovered at Spinks' home and at the scene of the eight bombings.

In addition, Schworm said Bray, using his own name, had rented a similar shed at the warehouse, Severna Office and Storage Co., in Millersville, last autumn but terminated the lease in late December.

Schworm said the ATF investigation is continuing and hinted that more arrests may occur.

During the bail hearing, defense attorney Robert Muse described Bray as "the perfect candidate for release . . . a family man with three children, one of them 3 weeks old." He noted Bray's membership in the Pro-Life Nonviolent Action Project and said he consistently advocates nonviolence from the pulpit at the Reformation Lutheran Church in Bowie where he is copastor.

Key evidence to the contrary, according to Schworm and prosecutor Robert J. Mathias, were three strands of hair matching Bray's that were taken from a piece of tape found attached to an explosive device at the Hillcrest Women's Surgi-Center in Southeast Washington after it was bombed early Jan. 1. Schworm testified FBI technicians found the hairs matched under "microscopic inspection" in more than 25 characteristics.

Under questioning by Muse, Schworm acknowledged that hair matches are not precise, as are fingerprints, and do not exclude all individuals other than a suspect.

Mathias argued that Bray would continue to be a danger to the community if released on bond because his religious fervor has caused him to go "beyond the law," regardless of his public advocacy of nonviolence.

The American Civil Liberties Union, whose office in southeast Washington was a target of one of the bombings linked by the ATF to Bray, came to Bray's defense today when told of Rosenberg's order barring Bray from coming within one mile of an abortion clinic or advocacy center.

"That's terrible," said Arthur Spitzer, legal director of the Washington ACLU. "If he wants to exercise his First Amendment right and picket peacefully I don't think there's any conceivable basis for forbidding him to do so."