For the third time in the last 18 months, the nation’s largest retailer has backed out of a deal to build a store in New York City.

Wal-Mart officials say a project on the south shore of Staten Island, which had been in the works since the beginning of 2005, collapsed because of the extensive environmental remediation required at the former industrial site.

“The remediation program needed at the site has caused a change in the site’s configuration to a point where it is no longer suitable for a Wal-Mart store,” a spokesman for the company, Philip Serghini, said.

Wal-Mart had partnered with an Ohio-based developer, Cedarwood Development Inc., to build a store near Tottenville, on an 18-acre site that Cedarwood was leasing from Lucent Technologies.

The process of gaining necessary city approvals and cleaning up the site were expected to take so long that Mr. Serghini said other stores in New York would have been built first.

“That store would not be the first one that we intended to open in New York,” he said.

A lobbyist for anti-Wal-Mart groups, Richard Lipsky, had a different explanation. He said Wal-Mart turned away from Staten Island due to the prospects of “too much political remediation.”

“If there was groundswell of support in the community, they could have dealt with the environmental issues,” Mr. Lipsky said. “No one in that neighborhood wanted that store.”

The project would require approval by the City Council under the city’s uniform land use review process for a zoning change. City Council members, including Speaker Christine Quinn, have opposed the presence of a Wal-Mart in the five boroughs, criticizing the company’s treatment of its employees and what they say is a negative effect on small businesses located near the chain’s outlets.

Even in a conservative district like the south shore of Staten Island, the Republican council member, Andrew Lanza, was said to oppose this Wal-Mart, according to community members. He did not return a phone message yesterday.

The retailer hired a former president of Staten Island, Guy Molinari, to lobby the city planning commission, the City Council, and the current president, James Molinaro, on the Tottenville project.

The president of the Staten Island Taxpayers’ Association, Dee Vandenburg, said she opposed the Wal-Mart based on projections of increased traffic and the environmental risk of building on a contaminated site.

“Any big box store of that magnitude — we just don’t have the infrastructure to support any more development of any kind on this island,” Ms. Vandenburg said.

The president of the Tottenville Center Association, June Delaney, said many local residents make the short drive over a toll bridge to Woodbridge, N.J., to shop at Wal-Mart.

“Wal-Mart is great, and people drive to shop there, so you may as well put them where there are vast amounts of open space,” Ms. Delaney said.

The anti-Wal-Mart lobbyist said the episode does not bode well for Wal-Mart’s prospects in more urban neighborhoods.

“If they are unable to manage a site in Tottenville, it is hard to imagine any site in the city where they need approvals, where they will be able to locate,” Mr. Lipsky said.

In April, Wal-Mart backed out of a potential site in Flushing that would have required City Council approval. Last year, the council was instrumental in blocking Wal-Mart’s entry into Rego Park, Queens.

Company representatives announced this spring that city residents are heading to suburban Wal-Mart stores in record numbers: City residents spent $128 million at six New York-area stores in 2005, 30% more than in 2004.

This summer Wal-Mart opened two stores within about 10 miles of city limits, in White Plains, N.Y.,and Kearny, NJ. The White Plains store, which occupies multiple levels in an existing nine-story building, is the type of urban model that Wal-Mart is now increasingly looking for in New York City.

“We are getting ideas and pitches and different opportunities every couple of weeks in the Bronx, Queens, Brooklyn, Staten Island, and fewer in Manhattan,” Mr. Serghini said. “Manhattan is a different animal, but we are interested here as well.”

“Chicago and New York are the two hottest spots right now in the country in terms of the struggle of Wal-Mart trying to serve its customers,” Mr. Serghini said.

In July, the Chicago City Council passed an ordinance requiring “big box” stores like Wal-Mart to pay a minimum wage of $10 an hour by 2010, in addition to at least $3 an hour worth of benefits. Next month, Wal-Mart will open its first store inside the city limits of Chicago, but the company has threatened that it could be the last unless Mayor Richard Daley vetoes the legislation.