The Herndon Planning Commission rejected yesterday a controversial proposal to build a tax-supported day-laborer site near a residential neighborhood, but the Town Council still will have the final say and remains on track for a vote later this month.

Officials with the social agency that wants to run the site for up to 150 workers said they are still trying to digest the accumulated criticisms of the plan that preceded the commission's 4 to 3 denial in a vote taken at 2:30 a.m.

"It's been given a blow, but it's not dead," said Bill Threlkeld, director of Project Hope and Harmony, the umbrella group that has applied for permission to build and operate the site, where contractors and homeowners could meet laborers seeking jobs.

Proponents say the challenge will be to address concerns expressed by residents without making so many concessions that day laborers will not want to use the site. Mayor Michael L. O'Reilly said the council, which will take up the matter in two weeks, is almost certain to demand several conditions.

"We will look at the application to see where change is feasible and realistic," said Joel Mills, a member of Project Hope and Harmony's executive council. "But there is a concern that so many conditions will be placed on how we operate that it becomes less and less feasible to do it successfully."

The designated site on the Loudoun County border would replace an informal site around a 7-Eleven parking lot. Several similar sites have been created throughout the region, including in Silver Spring and Langley Park.

In Herndon, an ordinance is being drafted that would make it a misdemeanor to solicit jobs curbside, but the town cannot legally outlaw day-laborer activity without zoning a site where it is permissible.

Herndon's struggle to cope with a day-laborer site has become a contentious chapter in the national debate over immigration policy. An unknown number of day laborers are in the country illegally; some estimates say as many as 85 percent of day laborers in Herndon are illegal.

Hundreds of critics have spoken out at public hearings like the one that stretched over seven hours Wednesday night into yesterday morning. Residents of nearby developments in Loudoun County as well as Herndon, several of them legal immigrants, said that they feared having strangers traipse through their neighborhoods en route to the site and that they worried its presence would decrease their property values. Others said they did not want their tax dollars used to support an enterprise that helps people who are in the country illegally.

After hearing the last of 130 speakers over the course of two nights, planning commissioners voted on a series of conditions. Among them were a limit of 100 laborers instead of 150, and a requirement that the site be closed on Sundays and federal holidays.

Frequently the debate veered from neighborhood concerns into a discussion of national immigration policy and assimilation.

"This is the United States of America, not the Diverse States of America," said William Tirrell Sr., a commission member who introduced most of the conditions. "We don't segregate ourselves in little pods of people. I'm not a hyphenated American. I'm an American. We need to take these folks and make them part of us. But I will not support tax dollars being used to support an illegal enterprise."

After approving the conditions, the commission voted not to recommend it.

The nonbinding vote was more a signal of the panel's displeasure than a serious hurdle. With some regularity, Herndon's council differs with the planning commission.

Ann V. Hull, a council member who often has criticized day-laborer sites, said she expects Project Hope and Harmony to modify its proposal to address the issues that opponents have raised. She also said she wants the group to justify the prediction that the official site can work.

But O'Reilly, who campaigned last year on a promise to improve the day-laborer situation, said he believes the concerns can be alleviated with a few modifications.

"I do believe this site can work and would work effectively," he said. "We're committed to trying to solve this problem."