In a blow to tenants’ rights, the state’s highest court ruled yesterday that landlords are not required to install radiator covers in apartments, even if children live there.

The unanimous ruling by the Court of Appeals will protect landlords from lawsuits if toddlers burn themselves on exposed radiators. The ruling is a victory for landlords and places increased responsibility on tenants to ensure that housing is safe for children.

Noting that no law explicitly requires landlords to install radiator covers, the decision said the responsibility for installing them lies with the tenant.

“The decision whether radiator covers must be supplied by landlords is thus left to legislators and regulators, who are in the best position to balance the harm prevented by this safety measure against its cost — a cost which, if imposed on landlords, becomes a part of the overall cost of rental housing,” the decision reads.

Judge Robert Smith, who was appointed to the court by Governor Pataki, wrote the opinion.

While the ruling deals only with the issue of radiators, a lawyer who represented the landlord in the case, Steven Prytowsky, said the decision goes toward settling the broader question of whether landlords must childproof their apartments.

Under current law, landlords do have some responsibility for taking certain precautions to protect children. In apartment units where children live, the law already requires that landlords remove or cover lead paint and install window guards, the decision reads.

The lawsuit before the court was filed in state Supreme Court in the Bronx in 2002 on behalf of Aaron Rivera, who was burned when he climbed atop an uncovered radiator in his family’s Bronx apartment, according to the ruling. The 3-year-old suffered severe burns and required skin grafts, an attorney for the family, Eric Popkin, said.

The family claimed to have repeatedly asked the landlord, Nelson Realty, to install a cover over the radiator, citing the risk it posed to children, according to the decision.

The plaintiffs argued that the landlord should have done so because legal precedent required landlords to keep property in “reasonable care under the circumstances,” according to the decision. The plaintiffs argued that a jury should get to decide whether that standard meant Nelson Realty was responsible for covering a radiator.

Yesterday’s decision affirms an appellate court’s ruling to throw the lawsuit out.

Mr. Popkin said similar lawsuits had resulted in landlords settling with the families of injured children. In New Jersey, Mr. Popkin said, a 1969 ruling by the state’s highest court allowed such suits to go to trial.