The Justice Department and the state of California yesterday accused the Hooker Chemical Corp. and one of its subsidiaries of knowingly polluting groundwater near Stockton with radioactive and cancer-causing hazardous wastes.

California Attorney General George Deukmejian asked the U.S. District Court in Sacramento to require Occidental Chemical Co. and Hooker, its parent firm, to clean up nearly 15 years of pollution. Deukmejian said that could cost $15 million.

In addition, the corporations could be liable for another $30 million in criminal penalties, according to Assistant Attorney General Steve Merksamer.

Deukmejian said he had obtained some Occidental internal memos indicating the firm "knowingly and willingly" concealed its dumping activities around its fertilizer and pesticide mixing plant at Lathrop, a town of about 3,000 near Stockton in the fertile San Joaquin Valley.

The wastes involved include radium residues from phosphoric rock, the chemcial DBCP, which is a suspected cancer agent, and pesticides chlordane, dieldrin, heptachlor and DDT, among others. They are discharged into six unlined waste ponds on the plant grounds and into a disposal ditch, said Deputy Attorney General Harold Eisenberg.

"We see this as a major action," Eisenberg said. "If we can get them to clean it up immediately provide fresh water to Lathrop and foot the bills, along with a reasonable civil fine then we'll be able to go to other problem companies and say we aren't afraid to take them on."

Hooker Chemical Co., a subsidiary of Occidental Petroleum Co. headquartered in Houston, is widely known for its involvement in the Love Canal industrial pollution controversy near Niagara Falls, N.Y., but legal action against polluting firms is just getting started. There have been only a handful of suits filed so far under the federal Resource Conservation and Recovery Act and none has yet come to trial.

Donald L. Bader, president of Hooker, expressed "shock and indignation" over the lawsuit. "This suit is unwarranted and will be vigorously resisted," he said in a formal statement.

"Not a single person has been injured by our waste disposal practices at the Lathrop plant and we are taking every precaution to see that no one will be."

An element in the suit involves Lathrop's 1960 permit to discharge wastes associated with the production of fertilizer.The California prosecutors hold that the firm began producing pesticide wastes without altering its orginial permit or seeking another.

The dangerous wastes first turned up in nearby wells that served a trailer park, the town school and several private homes, Eisenberg said. He added that the suit, in which the federal government joined, also would require a study of Hooker's 13 other storage and warehouse facilities in California, several of which also have waste ponds, to determine if any pollution is occurring from those.

Bader complained that his firm and the California attorney general's office had been working on a program to deal with the groundwater contamination and that the suit had caught the company by surprise. "For reasons unknown to Hooker Chemical, the attorney general has chosen to set aside months of constructive effort and take legal action," he said. "This procedure will be costly, time consuming and counterproductive."