Governor Pataki is using his final months in office to take on the teachers union.

Mr. Pataki on Wednesday night vetoed legislation that would have allowed 52,000 home-based day care workers to become quasi-state employees and join the city and state teachers unions.

Averaging $19,000 a year, home day care workers are overwhelmingly women and predominantly black and Hispanic. The United Federation of Teachers kicked off a campaign last summer to push Albany to pass legislation that would allow the workers – who are paid with state money as independent contractors – to be classified as state employees for the purpose of collective bargaining.

Proponents of the bill, including the labor unions, argue that these workers are overworked and underpaid. Critics of the bill worry that this would set the stage for turning these workers into full-fledged state employees with pensions and health benefits, increasing the state’s already considerable tax burden.

“I have never seen a group of workers who are more exploited in the 21st century,” the president of the United Federation of Teachers, Randi Weingarten, said. She accused the New York Public Welfare Association, which opposed the bill, of wanting to keep day care workers “voiceless” so that they can continue to exploit them.

The executive director of the Public Welfare Association, Sheila Harrigan, said that she supported increases in state and federal funding for day care, but said that the workers were not exploited.

The union has enticed workers with the hopes of higher wages, paid days off, and a pension. The bill passed easily through both the Democrat-controlled Assembly and Republican-controlled Senate, and there is already talk of an override.

The workers are independent businesswomen who are paid by the state to care for the children of low-income families. In order to join a union they must establish an employer, which in this case, if the legislation became law, would be the state.

Parents who qualify for the subsidy choose from a number of state-approved childcare providers. The providers work out of their own homes and are directly paid by the state.

“Most fundamentally, the bill expands our already large public sector even further and that would set the stage for still further tax increases,” said the director of research at the Public Policy Institute of the Business Council of New York State, Robert Ward.

Mr. Ward, an opponent of the legislation, said that the bill would set a precedent that other unions would want to follow. “We would end up with many tens of thousands of additional workers shifted to the public payroll,” he said.

If the workers each received a $1 an hour raise, Mr. Ward argued that it could cost the state an additional $75 million a year. If they later bargained for pensions and health care, he said that it could cost billions more.

Other states, including Illinois, Iowa, Washington, and Oregon, have already given day care providers in similar programs the right to unionize.

The New York bill is sponsored by Senator Spano, a Republican from Westchester who only narrowly won election, and Assemblyman Espaillat, a Democrat from Manhattan.

In the veto message, Mr. Pataki said that the bill would put the state’s $315 million in federal day care funding at risk.

Ms. Weingarten said that no other state has lost its federal funding after allowing day care workers to unionize. She said that Illinois has already reached a contract with the workers that allowed for a wage increase without jeopardizing federal funding.

In the northeast section of the Bronx, Bridget Carruth has been taking care of children in first floor of her home for the past 15 years.

She calls her daycare center TKS Prep and says that it’s more than babysitting; she is preparing the children for kindergarten.

Every morning she opens her doors at 7 a.m. and says goodbye to the last child around 6:30 p.m. After that, she stays around with her small staff cleaning up and preparing lessons for the next day. She said that she makes anywhere from $4,000 to $19,000 a year and is licensed to care for up to 20 children.

“We need health insurance, we need a pension, we would like to get money for the children, we would like to get paid for sick and vacation days,” Ms. Carruth said. “We have never been able to do anything but with the union we will have the power to bargain to get these things – this is just a delay, really, we are not daunted at all.”

A political consultant, Scott Levenson, who has worked with labor groups, called Mr. Pataki’s veto “a slap at the UFT.” He said the teacher’s union is one of the most powerful unions in the state and that with thousands of additional members it would have become even that much more powerful.

“If you think that that the UFT contracts have been good for New York City schools than you should love this bill,” Mr. Ward said.

Mr. Pataki is also seeking, in his final months in office, an increase in the number of charter schools in the state, a step that the UFT has been resisting.