A Con Edison oil spill over the weekend saddled NYC Ferry service with delays Tuesday, the service said.

The spill happened when a transformer at a Con Ed substation at 89 John St. in Brooklyn ruptured on Sunday afternoon.

“A transformer containing approximately 37,000 gallons of insulating oil used with electrical equipment, failed on Sunday May 7 at 12:23 p.m., causing much of the oil to be released within the station property in addition to the East River,” the company said in a statement.

The agency said it is working with the Coast Guard and the New York Department of Environmental Conservation to clean up the spill.

“We continue to assess the volume of oil that migrated to the East River, and how much oil remains in the ground on our property,” it said in a statement.

Con Ed also said the transformer failure caused “a system voltage dip that impacted the MTA’s signaling systems on Sunday.” The power dip affected the DeKalb Avenue station, forcing service changes on the D, N, Q and R trains for about an hour and a half, the Metropolitan Transportation Authority said.