SALT LAKE CITY (AP) _ A defunct storage company and its former president have been charged with conspiracy to illegally dispose of hazardous wastes, including surplus napalm bombs, near people's homes, officials said today.

''This case represents perhaps the most serious type of environmental misconduct,'' U.S. Attorney General Dick Thornburgh said at a news conference.

He said that the 12-count federal grand jury indictment was the first federal felony prosecution of environmental crime in Utah. The company, EKOTEK, and its officers had ''duped environmentally conscious businesses into believing that waste materials were being properly disposed of,'' Thornburgh said.

The indictment alleges the company knowingly burned, poured out and improperly stored a variety of hazardous wastes in violation of an array of state and federal laws in the middle and late 1980s. The site is now on the Superfund cleanup list.

Among the incidents leading to the indictment was that of a 17-year-old boy who reported that his shoe began to bubble and disintegrate after he accidentally stepped in some liquid while running near the site, officials said. Tests have been conducted around 125 homes near the site.

The charges were filed Wednesday afternoon in U.S. District Court.

Named in the indictment were EKOTEK and Steven M. Self, the company's president. The company was involuntarily dissolved Nov. 1.

If convicted on all charges, Self could face a prison term of up to 45 years, and he and the company would face up to $24 million in fine.

Company vice president Steven F. Miller pleaded guilty Wednesday to felony charges of conspiracy and violations of federal resource conservation and recovery laws and the Clean Water Act, Thornburgh said.

Miller was allowed to plead guilty in exchange for his cooperation in the prosecution of Self, authorities said. He could face up to 13 years in prison and a $750,000 fine; sentencing was set for July 10.

Self and his company are alleged to have purchased millions of gallons of oil and solvents and burned them as fuel in a refinery in northern Salt Lake City about three miles northwest of the downtown area. The burning violated the federal Clean Air Act. In other cases, wastes were illegally poured into storm drains or stored in an improper manner.

State Department of Health officials said tens of thousands of gallons of the wastes have leaked into the ground and contaminated nearby homes.

In addition, the indictment alleges that in July 1986, Self arranged to accept two napalm bombs for ''testing, storage and treatment'' from the Navy Weapons Support Center in Fallbrook, Calif. State explosives experts had to haul the bombs away and dispose of them in 1987.

The site, currently being cleaned up through the Environmental Protection Agency's Superfund program, reportedly still contains almost a half million gallons of used petroleum products and other toxic wastes in leaking tanks and drums.

Among the chemicals found at the plant were poisonous polychlorinated biphenyls, or PCBs; methylene chloride, which has been linked to tumors; and the toxic solvents n-butyl acetate, methyl ethyl ketone, toluene and xylene.

The site was identified for EPA cleanup in 1988. The agency has identified 32 companies as being responsible for cleanup of approximately 500,000 gallons of aging, used petroleum products and other hazardous wastes at the site.

EKOTEK-Petrochem formerly operated an oil refinery on the site. The state Division of Environmental Health had determined it might pose a risk to nearby residents and the EPA took soil samples from land surrounding about 125 homes earlier this year.