The messages of the two contenders in an increasingly contentious governor's race collided on a Providence sidewalk yesterday.

On one edge of the concrete, Democrat Myrth York, playing off her new TV attack ad, briskly and coolly delivered an indictment of Republican Donald L. Carcieri as a "corporate CEO" at Cookson America who "pursued profits at the expense of people" by presiding over a company she said helped ravage a Brazilian rain forest and spew poisonous lead into a Philadelphia neighborhood.

About six feet to her left stood Carcieri himself, who crashed the news conference outside his former company headquarters at 1 Union Station to watch York's speech, then declared her comments a sign of "a campaign in desperation."

"I've got 13 grandchildren," he said. "You think I'm not concerned about those kinds of things? Of course. And it's really disturbing to me we're going to use an issue like this to try to divert all the attention away from the fact that frankly she hasn't got the experience and the leadership to go forward and run this state."

The skirmishing extended to campaign staff. As a Carcieri aide tried to videotape York's comments, a York aide stood in front of him armed with a large piece of bright yellow poster board, blocking his sight line.

York press secretary Ray Sullivan said he ordered the blocking maneuver because "We're not going to allow a press conference to talk about substantive issues to be used in a commercial for a political negative attack ad."

With two weeks to go until the Nov. 5 election, the change in tone "clearly demonstrates the race is tightening up, and both sides are preparing for real battle," said Marc Genest, a University of Rhode Island political science professor who is spending the year at the Naval War College in Newport.

Brown University political science Prof. Darrell West, on the other hand, believes the calendar, more than a tightening race, is driving the turn toward a feistier campaign.

"This is when candidates start going after one another," said West, who expects to release his own poll numbers this week.

York's attacks on Carcieri focused on two accusations. One is that, as a "top corporate executive at Cookson America" Carcieri helped "personally broker" what she called a "tin mining deal" for his company.

"Cookson's profits came from encouraging irresponsible mining practices that destroyed rain forests and polluted ground water," she charged, adding, "An accident at the mine killed 15 workers."

The other focused on a plant owned by a Cookson subsidiary, Anzon, in Philadelphia, which she said was "repeatedly fined for violating pollution and safety standards for industrial emissions of one of the most dangerous substances around, lead" in the 1980s.

"Don Carcieri's company poisoned an entire neighborhood, even a playground," she said, charging that as a company vice president of operations at the time, Carcieri held some responsibility for what happened.

To buttress her accusations against Carcieri, York brought with her Sheila Dormody, representing the state branch of Clean Water Action; Dr. Nick Tsiongas, a former state lawmaker and director of Ocean State Workplace Health in Pawtucket; and Jim Celenza, director of the Rhode Island Committee on Occupational Safety and Health. Each took turns ripping further into Carcieri, as York stood nearby, her hands clasped.

whose presence she did not acknowledge — "would not put the health and safety of the people of this state first" as governor.

Carcieri countered that his company had never mined tin in Brazil, only purchased it, and should not be held accountable for the tin mine's environmental record.

"We bought some tin from a Brazilian mining company," he said. "It's sort of like when I buy a teddy bear for my granddaughter that's made in China: does that mean I'm responsible for everything that happens in China?"

As for the Philadelphia plant, Carcieri said it was an "old plant" and that under his leadership as the company's chief executive, "we spent millions of dollars to make sure that plant was in conformance with all of the [federal] EPA regulations."

"Every once in awhile when you're running a plant, the plants have accidents," Carcieri said. "And you respond as quickly as you can, as fast as you can ... that's what we did.

"For someone to assume and imply I'm not going to be sensitive to the environmental concerns of this state, I find absolutely absurd," he declared, his voice quavering. "And I take that personally, maybe more than I should. But I'm not going to sit by and have somebody imply I don't care about this state."

Noting York had said she would not attack first, he asked, "What other pledges or what other intentions do we believe?"

York countered that she was simply examining Carcieri's record, and would "continue to discuss the issues" in the final two weeks.

Carcieri would not say whether he would strike back.

"We're going to have to look at it," he said, but added, "If someone is going to start accusing you of flagrant things, you can't sit back."

Carcieri's former boss at Cookson, Richard Oster, a political ally, happened by the news conference and listened in. Oster said Carcieri did not have "full responsibility" for the Philadelphia plant until he became chief executive in 1991, and deserved credit for keeping the plant open and saving jobs while spending money "to get this plant right."

As for the mining allegation, Oster said, "To claim [the mine company] stripped the rain forest is far-fetched, incorrect. And to say Cookson did a tin mining operation is an outright lie and deception, and I don't expect that kind of thing from her."

West sees York's attack as designed to give voters negative feelings about Carcieri, and said its environmental message is specifically targeted toward "moderate, independent voters, people who are the classic swing voters who make up their minds at the end of the election."

Genest called York's attack "right out of typecasting 101," but dangerous because it could make her "seem desperate and shrill."

"The key will be: Is Carcieri someone that people believe to be cold-hearted?" he said. In response, he suggested, Carcieri must push a nice-guy image while attaching York "as closely as possible" to legislative leaders and to Democrats' failure to bring about reforms.