NEW YORK — The federal government on Thursday announced its plan to clean up a Superfund site in New York City where radioactive material was once processed to develop the atomic bomb.

The U.S. Environmental Protection Agency said the $39 million job, which could take years, will force out businesses still operating on a block in Queens where buildings, the soil and sewers were contaminated with radioactive material. Protective measures have been in place since 2012.

The source of the industrial waste was the Wolff-Alport Chemical Company that operated on Irving Avenue in the Ridgewood neighborhood from 1920 to 1954, according to Elias Rodriguez, the EPA spokesman in New York. The company processed monazite sand, extracting from it a radioactive element called thorium for the federal government as part of a program that began with the top-secret Manhattan Project that led to the testing of the first nuclear weapons during World War II in New Mexico.

The now-defunct company disposed of thorium waste on its property and into the Queens sewer.

Given the contaminated waste, the owner of the Celtic Custom NYC motorcycle repair shop, Sandy Frayman, said on Thursday that he wouldn’t want to stay, “but we’re worried what’s going to happen to us.”

He said it’s practically “impossible” to find affordable space in New York City for his business. “And if you go too far, you lose a lot of customers.”

The businesses being forced out — including several auto body shops, a deli and a Mexican tavern — are expecting some kind of government compensation. But Frayman said that won’t cover higher rents indefinitely. “This is a permanent move without a permanent plan; it’s like someone gets shot and you put on a Band-Aid.”

He added: “We hope the government is going to take care of us, since they created the problem originally, even if it was not intentional.”

The public is invited to voice concerns to the federal agency — either by email, regular mail and telephone, or by showing up for an open public hearing on Aug. 16 at a nearby day care center.

Authorities had already taken action to protect people working for the half-dozen businesses, a warehouse and offices.

“Because of earlier EPA response actions, and those of state and city agencies, there is no immediate threat to nearby residents, employees or customers of businesses along Irving and Cooper Avenues,” the EPA said Thursday in a statement, adding that in 2012, the agency installed $2 million worth of radiation shields, including layers of concrete, lead and steel under building floors and sidewalks.

Long-term risks from radiation include cancer, said Catherine McCabe, the acting regional EPA administrator.

Following an EPA evaluation, buildings will be razed and excavation will start to remove more than 24,000 cubic yards (18,000 cubic meters) of contaminated soil, sediment and debris.

An exact date for the cleanup will be set when the evaluation is completed.

____

EPA cleanup plan: www.epa.gov/superfund/wolff-alport