The Supreme Court yesterday ruled unanimously that states may be found guilty of discriminating against the handicapped even if there is no proof that state officials intended to do so.

Justice Thurgood Marshall, writing for the court, said Congress passed the 1973 Rehabilitation Act because it saw discrimination against the handicapped as "most often the product, not of invidious animus, but rather of thoughtlessness and indifference -- of benign neglect."

The ruling, called a "major advancement" by advocates of rights for the handicapped, nevertheless went against a group of Tennessee Medicaid recipients because the court said the state's decision to reduce benefits was permissible under the 1973 law.

In the second of five decisions handed down yesterday, the court ruled that filing for bankruptcy can, in limited instances, protect owners of hazardous-waste dumps from the costs of cleaning up the sites.

The unanimous decision, written by Justice Byron R. White, in a pollution case from Ohio, emphasized that the court was deciding whether filing for bankruptcy would have that effect only when the state had taken over the site, in effect, "dispossessing" the owner.

Ohio officials called the narrow ruling "livable" because, even though it went against them, it leaves open other actions, such as criminal sentences and fines, that states might pursue to punish polluters.

In the other cases yesterday, the court said:

* Individual taxpayers must pay penalties for late tax returns even if their accountants or lawyers were to blame.

* Internal Revenue Service investigators do not need court approval to force companies promoting tax shelters to turn over information about individual clients.

* States have no power to tell counties what to do with payments from the federal government in lieu of taxes.

In the case involving the handicapped, Alexander v. Choate, the state of Tennessee was joined by the Justice Department in arguing that the 1973 law was aimed at stopping only intentional discrimination against the handicapped.

Marshall rejected that view, saying it would be "difficult if not impossible" to ban most discrimination against the handicapped if the law outlawed intentional discrimination only.

Architectural barriers, such as high curbs or a lack of elevators, he said, are examples of barriers that could be discriminatory even though they were "clearly not erected with the aim or intent of excluding the handicapped."

Marshall also rejected the suggestion by advocates of rights for the handicapped that the law prevented states from taking any action that affected handicapped persons more than others.

Marshall said Congress did not intend to require "handicapped impact statements" before states established programs with federal dollars.

Tennessee's reduction in annual Medicaid-funded hospital days from 20 to 14, which the state said would save millions of dollars, is permissible, Marshall concluded, because it is "neutral on its face," does not have "a discriminatory motive and does not deny the handicapped access to or exclude them from the particular package of Medicaid services" that the state chose to provide.

In the hazardous-waste case, Ohio v. Kovacs, the state was joined by 30 other states and the federal government.

They asked the high court to overturn an appeals-court ruling that the owner of the Chem-Dyne waste site in Hamilton, Ohio, could shield himself from paying for a court-ordered cleanup of the site by declaring bankruptcy.

The appeals-court decision "could be interpreted to say you could 'dump and run' " under protection of bankruptcy law, Ohio assistant attorney general Dennis Muchniki said yesterday. The Supreme Court "rejected that idea; that much is pretty clear," he said.

The case began when the site's owner was ordered to clean it up but did not. Ohio officials successfully sought a court-appointed receiver to correct the situation.

"As wise as this course may have been, it dispossessed the owner , removed his authority over the site and divested him of assets that might have been used by him to clean up the property," White said. Ohio could not try to obtain more money from him after he filed for bankruptcy, White wrote.

White, in announcing the ruling, noted that it applied to "the peculiar circumstances of this case." In the written opinion, he emphasized a broad range of criminal and civil sanctions the state could seek to force dump owners to pay for cleanups and said the court was not ruling on the propriety of those options.

White also authored a narrow 5-to-4 ruling that South Dakota cannot tell its counties what to do with federal funds under the Payments in Lieu of Taxes Act, which compensates counties with extensive federal lands for which no state or local taxes are paid.

About 1,700 counties in 49 states share almost $100 million a year in such payments.

South Dakota prescribed how counties must distribute the funds, but the court ruled that Congress intended that counties should decide how to spend them.

The case is Lawrence County v. Lead-Deadwood Schoool District No. 40-1.

Writing in a unanimous ruling in U.S. v. Boyle, Chief Justice Warren E. Burger said Congress "placed the burden of prompt filing" of taxes, on taxpayers, not on "some agent or employe . . . . "

While late-filing penalties that can amount to 25 percent of taxes owed can be excused in some cases, "it requires no special training or effort to ascertain a deadline and make sure that it is met," Burger said.

Marshall also wrote a unanimous opinion that the IRS does not need court approval to issue a summons to a taxpayer to investigate the taxpayer and other, unknown persons.

The IRS generally needs court approval to demand documents from a source other than the person directly involved.

Marshall said no such approval is needed when the IRS' purpose is to investigate the taxpayer's liability and those of others doing business with the taxpayer.