ABERDEEN PROVING GROUND, MD. -- A federal grand jury is investigating Army and civilian officials who oversaw the operation of a deteriorated test facility where highly hazardous substances were mishandled, according to a published report.

The investigation centers on alleged violations of federal environmental and worker safety laws involving handling, storage and disposal of dangerous substances at the proving ground, the Baltimore Sun reported yesterday.

The substances included components of lethal nerve agents, sources told the newspaper.

FBI agents and federal prosecutors were poring over scores of Army documents subpoenaed by the grand jury May 6 and delivered May 19. Some of the records allegedly had been falsified, and supervisors had lied in an attempt to cover up questionable practices at the plant, sources said.

The investigation has uncovered evidence that the Army appeared to have used the plant for storing hazardous wastes from bases around the country as well as from the proving ground, the sources said.

John A. Yaiquaint, a spokesman for the base commander, Maj. Gen. Charles F. Drenz, referred all questions about the investigation to Breckinridge L. Willcox, U.S. attorney for Maryland.

Willcox declined to confirm or deny the investigation.

Sources said the grand jury asked for records dating to January 1982 from the base headquarters and from the Army's Chemical Research, Engineering and Development Center, which operated the plant where the hazardous materials were stored.

Before it closed in February 1986, the plant performed preproduction studies on the Army's binary chemical weapons systems, scheduled to go into production this year.

The dilapidated, 46-year-old pilot plant building is at the base's Edgewood Arsenal, near the upper end of Canal Creek, a tidal stream that flows into the Gunpowder River, which flows into the Chesapeake Bay.

The newspaper last year had reported problems at the plant, including the alleged illegal burning and dumping of chemicals and unsafe exposure to workers.

In March, the Army acknowledged problems at the plant and said the plant would be closed except in the case of emergency.