The Maryland House of Delegates voted tonight after intense debate to prevent Maryland businesses from taking advantage of corporate tax deductions that would be allowed automatically under new federal tax laws.

If the measure is approved in the Senate, businesses will not be able to take tax credits as rapidly for equipment that depreciates or take advantage of special investments on leases. The new federal law, which Maryland copies unless the legislature votes otherwise, would allow the corporations to speed up the rate of depreciation and pay fewer taxes.

Supported heavily by labor and public interest groups, the bill has won little enthusiasm in the business community. Business leaders failed to win Gov. Harry Hughes to their side, even though Hughes has attempted to portray his administration as one sympathetic to development interests in the state.

The business community argued that a failure to grant tax deductions would reduce business investment and cause higher unemployment.

Del. Louis L. DePazzo (D-Baltimore County) echoed these concerns tonight by warning that the bill's passage would "send a bad message that Maryland is antibusiness."

Hughes refrained from taking a position on the bill until late last week, but finally opted to support decoupling--the term used when a state varies from federal tax law--at the end of this year.

The 78-to-36 vote came after a spirited 25-minute debate in which supporters of the legislation argued that the state would lose enormous sums of revenue if businesses were allowed depreciation tax credits.

"The federal government is cutting our revenues on the one hand, and cutting the assistance we have come to rely on for programs on the other," said Del. Gerard F. Devlin (D-Prince George's) in support of decoupling.

Del. Dennis McCoy (D-Baltimore) said "the state would pay a significant penalty. To the state treasury, it's horrendous."

Delegates who supported the bill have also argued that it would be unfair to citizens to raise the gasoline tax by 4.5 cents over the next two years while allowing tax deductions to corporations. The gasoline tax was approved last week.

There are no clear estimates on the amount of money that the state will receive through the taxes on depreciation if it decides not to conform to federal law. The Citizens for Tax Justice, a coalition of public interest groups that has taken the lead in pushing for decoupling, has estimated that as much as $300 million to $400 million would flow into the state treasury over the next five years.

In other action tonight, the House passed by a 101-to-0 vote a bill to allow localities to grant exclusive cable television franchises without the threat of antitrust suits.

The delegates also approved a bill that would prevent banks from witholding canceled checks from customers without a written waiver.