A proposed Nascar racetrack on Staten Island has split New York’s smallest borough and is the dominant topic of discussion at community board meetings.

At the monthly meeting of the pro-Nascar Mariners Harbor Civic Association, Mayor Bloomberg was asked for his opinion. Although he said he agrees that the racetrack would boost business, Mr. Bloomberg said that before signing on, he would have to know how the traffic situation would be handled. “That’s a very big problem,” he said.

Earlier in the week, the South Beach Civic Association voted unanimously to oppose the track after hearing from the president of Staten Island Citizens Against the Track, Ronald Lauria. “There’s 457,000 people on Staten Island and 267,000 cars. That’s a higher concentration than any other borough,” he said.

Additional opposition to the Nascar project, which would be the largest stadium in the city, is coming from residents concerned about the environmental impact on Staten Island, which has a number of protected wetlands in the surrounding area. The expected noise levels of track events are also an issue.

According to officials of the International Speedway Corporation, which last December bought the undeveloped parcel of land in the Bloomfield section of Staten Island for $110 million, the stadium will host only three stock car races a year. The rest of the time, the stadium could be used for a limited number of smaller events.The ISC also claims that the noise of a race will be lower than that of a jet plane or a rock concert.

The ISC’s director of corporate development, Michael Printup, told The New York Sun: “The company is providing, at its own expense, ferries and buses that will mitigate the event traffic. The event traffic on the six weekend days of the year will be no heavier than the Monday to Friday rush hour.”

The proposed project would consist of an automobile raceway with grandstand seating for up to 80,000 spectators and a retail center of approximately 620,000 square feet. The project also would include parking and various transportation facilities and infrastructure, including a ferry landing and helicopter pad.

Nascar supporters point out that Englishtown, N.J., was largely undeveloped before Nascar built Raceway Park there. The races, they say, were instrumental in developing Englishtown into a thriving area that generates significant tax revenue.

The Department of City Planning will hold a public hearing on the Nascar project on April 27 at P.S.80, the Michael Petrides School, to discuss the environmental impact and hear comments from interested parties. The process for approval from the City Council is expected to take a year and a half. Even if it passes, the first race would not take place until 2010.