Charging a "cover-up" by Occidental Chemical Co., Dr. Harvey F. Collins of the California Department of Health has told a House panel that Occidental's Lathrop, Calif., plant wastes have posed "a significant health hazard" to neighboring families.

Collins told the House Commerce oversight subcommittee Tuesday that the company knew, but did not disclose for four years, that fertilizer and pesticide wastes from its plant were polluting local drinking water wells.

Solvents found in a well 500 feet from the plant were a "significant health hazard" and state officials would have shut down the well years ago if company officials had disclosed the problem, he said.

Occidental Chemical is under investigation by the state attorney general's office and could face fines of $25,000 a day for violating pollution laws.

Internal company memos, reported Monday by the Los Angeles Times and released Tuesday by the subcommittee, showed that company officials deliberately misled local residents and state officials about the easte pollution of local wells.

Rep. Albert Gore Jr. (D-Tenn.), charged that high corporate officials at Occidental Chemical, a subsidiary of Occidental Petroleum Co., may have been involved in "what might be called a cover-up." Collins agreed.

"Every person who decries the inflationary effect of regulating hazardous chemical waste disposal ought to direct his or her attention to this sequence of comments within this corporation," Gore said, referrig to the company's secret memos.

"The [company officials] wouldn't drink the water, but they were content to continue dumping in the soil where it would contaminate their neighbor's well. They were not going to do anything about it because there had been 'no government pressure,'" he said, citing a 1976 memo.

Gore said he would cosponsor legislation by Rep. George Miller (D-Calif.) that would levy two-year prison terms and/or $50,000 fines agianst corporate officials who knowingly mislead employes, officials or the public about the hazards of their products. The legislation will be cosponsored by subcommittee Chairman Bob Eckhardt (D-Tex.) and 39 other House members.

"We have case after case where these dangers are known but they're kept bottled up in the boardroom," said John Lawrence, a Miller aide who is helping draft the bill.

Collins testified that California's $2 million annual chemical waste disposal monitoring program, funded half by industry taxes and half by federal grants, is a model for the nation. California has fewer "old industry" abandoned chemical dumpsites than most states, he said.

Collins also said that California officials support the Carter administration's recently introduced "superfund" proposal - a $1.6 billion, four-year program for cleaning up hazardous dumpsites. Chemical and oil-company taxes would pay for 80 percent of the fund, and taxpayers would pay the rest.