A federal grand jury in Michigan has subpoenaed thousands of documents from Hooker Chemical Corp. to determine whether company officials falsified information on dumping permits in order to dispose of a deadly pesticide waste.

Sources familiar with the investigation said yesterday that the grand jury, which was empaneled last year in Grand Rapids, Mich., is looking into the possibility that Hooker officials lied on applications for dumping permits at its Montague, Mich., plant site.

In October, Hooker and Michigan signed an agreement obligating the chemical company to spend an estimated $15 million to clean up the Montague site.

Michigan authorities said Hooker dumped more than 30 types of chemicals, including some which cause cancer, at Montague. Some of the chemicals have leaked from the site into White Lake, a nearby arm of Lake Michigan, state officials said.

According to sources, the federal grand jury is evaluating the documents it gathered. Sources said the panel is expected to begin focusing its investigation on specific Hooker officials and calling witnesses in about a month.

James S. Brady, U.S. attorney for the western district of Michigan, said yesterday, "There is a criminal investigation and it has proceeded to the level of a grand jury investigation." Brady declined to comment further.

Sources said, however, that federal investigators are seeking to narrow their criminal investigation to specific Hooker officials who filed documents over the last 10 years.

A spokesman for Hooker said yesterday that the Niagara Falls, N.Y., firm was aware of the investigation. "We received a subpoena several months ago and we have turned over documents to the grand jury," the spokesman said.

Other souces in Michigan said yesterday that the FBI last week requested copies of Hooker's water discharge documents for more than 10 years from the Michigan Department of Natural Resources. The documents list the type and mount of hazardous material company officials said they were releasing at the Montague site.

Hooker's hazardous waste dumping pactices have been the focus of intensive federal and state probing since 1978 because of its chemical dumping at the Love Canal in Niagara Falls, N.Y.

Last month the Justice Department filed suits against Hooker and its corporate parent. Occidental Petroleum Corp., seeking more than $124 million to clean up Love Canal and other Niagara Falls sites.

In a separate court action also filed last month, the Justice Department and California accused Hooker and a subsidiary of knowingly polluting groundwater near Stockton, Calif., with radioactive and cancer-causing hazardous waste. The chemical company denied the charges.