The more than 70,000 National Guardsmen, reservists and active Army troops who used Virginia's Fort A.P. Hill for training exercises last year ran no risk of dioxin contamination from an old chemical spill, an Army spokesman said yesterday.

"Some may have walked through the area," said Army Maj. Jay Craig, "but the closest anyone came to staying there were units camped on concrete pads more than 600 feet" from the storage shed where the spill, first noticed in 1978, occurred. The shed was used until the late '70s to store herbicides now considered toxic, Craig said.

The Army also confirmed that a large spill of the pesticide DDT took place on the base in 1982, but said the accident was cleaned up as soon as it occurred and was not in an area used by the National Guard.

Chemical hazards at the 76,000-acre post became an issue last week, when the Army disclosed that dioxin residue from an earlier herbicide spill was found on land used by some of the 32,000 Boy Scouts and staffers who used the facility for their 1981 national jamboree.

In testing this year, the Army found that leakage from two 55-gallon drums of the herbicide Silvex had contaminated the ground around and under the shed in which the drums were stored until 1978.

Test results released by the Army last week showed that dioxin, a toxic contaminant found in the now-banned Silvex, was present at levels of 228 parts per billion under the shed and roughly 3 parts per billion 150 feet downhill.

The Environmental Protection Agency and the federal Centers for Disease Control have established one part of dioxin per billion parts of soil as the acceptable risk limit, but the CDC announced this week that chances of contamination during the Boy Scouts' brief exposure in 1981 posed no danger.

The author of a National Wildlife Federation study of environmental hazards on Virginia's military installations and a U.S. congressman, however, said this week that the spills, as well as other toxic waste management practices at A.P. Hill and other military posts, show that the military should be subject to the same toxic-waste regulations as private property under the Environmental Protection Agency's Superfund program.

Department of Defense and other federal properties are exempt from Superfund enforcement. The Defense Department has operated its own toxic site identification and cleanup program since 1975. A recent draft of a government assessment of that cleanup effort, commissioned by Reps. James Florio (D-N.J.) and Vic Fazio (D-Calif.), criticized the military's program as ineffective and recommended greater coordination between military, state and federal environmental authorities.