The New Jersey Supreme Court has let stand a lower-court ruling that a Gloucester County family must pay part of a $4 million fine and a $2 million environmental cleanup cost after the family acquired a contaminated thermometer plant and converted it into a children's day-care center without removing the building's toxic mercury vapors.

The decision last week not to hear the appeal caps a 10-year legal battle that started soon after the state Department of Environmental Protection discovered the Kiddie Kollege day-care center had opened in 2004 in an abandoned factory in Franklinville. About 100 babies and children were exposed to vapors that can cause brain and kidney ailments.

After the DEP shut the center in 2006, the agency had the building demolished and the site remediated, and then assessed the clean-up cost to real estate agent James Sullivan III, his three siblings, and the former factory owner, Philip J. Giuliano. The agency also ordered the Sullivan family and Giuliano to pay a $4 million fine for neglecting the clean-up, but did not specify how the costs should be divided.

The state Department of Environmental Protection assessed the Sullivan family and Giuliano a total of $4 million in fines or damages, a rare action by an agency that has catalogued more than 14,000 contaminated sites in the state.

The Sullivan family and its corporate entities appealed the DEP's action, but an appeals panel upheld the DEP in January. The Sullivans then appealed to the Supreme Court, which declined to hear the matter, a courts spokesperson said Wednesday.

The family's attorney, Alan C. Milstein, and Giuliano, who has not been represented by a lawyer in the matter, could not be reached for comment Wednesday. Giuliano, who operated the Accutherm plant, had not filed an appeal.

Sullivan, who owned a real estate office next to the abandoned factory, had acquired the building through a partnership, the Navillus Group, with his brother, Drew, and his sisters, Sandra Lyons-Sullivan and Terri Clay.

The news that the day-care center had opened in a toxic plant had captured national attention and led to changes in state and federal laws to better protect children from such exposure. The state Health Department tested some children and found several had high levels of mercury in their bodies initially. But when the levels dropped later, the department said no lasting affects were expected.

856-779-3224 @JanHefler