New regulations, put into place Friday in reaction to the Kiddie Kollege scandal, require day-care centers in New Jersey to ensure there are no contaminated sites within 400 feet of the property before they can obtain a license to open.

The mandatory rule, posted without fanfare on the Department of Environmental Protection Web site, caught at least one day-care center off guard, delaying its scheduled opening yesterday.

John Brennan, president of Brennan Environmental Inc. in Summit, Union County, said a client called his firm Friday to say the DEP was requiring him to do an environmental review on the eve of opening a day-care business. Brennan, who does environmental testing and cleanups, declined to divulge the day care's name but said he believes the new regulation is a good one.

"It's similar to the 'due diligence' we do for other commercial companies to make sure there is no contamination on a property before it is purchased," said Brennan. " 'Due diligence' is doing a visual inspection, investigating what the past uses were, interviewing neighbors, and finding out if there was any environmental impact to a property," he said.

Banks frequently require "due diligence" before granting a loan to buy a commercial property, but many day-care centers have escaped such scrutiny when they open in a house or rent a building.

Tom Bell, spokesman for the state Department of Children and Families, said yesterday that "some day-care centers are receiving letters" informing them of the new environmental review and testing that they must perform before obtaining a license to open. Bell, whose agency oversees day-care centers, said he could not yet provide an exact number affected.

The regulation requires a day-care center to contact the DEP so that a record search can be made of a 400-foot radius of the property. If contamination is discovered, the DEP would determine what remediation needed to be done, and a certified environmental company would need to be hired.

In recent weeks, the environmental agency and the DCF have come under fire after DEP inspectors discovered that Kiddie Kollege in Franklinville had opened without their knowledge two years ago in a former mercury thermometer factory. The DEP failed to enforce a cleanup it had ordered at the contaminated factory, and the children and family agency did not check on whether the site was toxic before issuing a license.

Health officials said that 20 of the 60 children who attended the now-closed Kiddie Kollege showed elevated levels of mercury exposure, but that the amount should not cause serious long-term effects.

After the closure of Kiddie Kollege in July, two other day-care centers in Franklinville were found to be on or near contaminated sites. According to the DEP, the Through the Years day care, now closed, operated on a former fuel company site contaminated with PCBs, degreasers and fuel oils. And the Franklinville Preschool Academy was found to be near a gas station with leaking underground tanks. The DEP has told the current and former station owners to conduct air and water tests.

State inspectors are checking to determine whether any other day-care centers are on or near toxic sites. Elaine Makatura, a spokeswoman for the DEP, said yesterday that she knew of no others.

The state Attorney General's Office is conducting a criminal investigation into how Kiddie Kollege was allowed to operate without cleanup of the mercury, and Gov. Corzine has appointed a team of cabinet members to make recommendations on ways to keep day-care centers off contaminated sites.