Con Edison says it's working to contain an oil spill in the East River.

The utility says a transformer at one of their Brooklyn substations failed Sunday afternoon, causing oil to spill into the river.

The equipment failure also caused problems with the subway signal system, leading to service disruptions.

Officials say the transformer was holding about 37-thousand gallons of oil, but it's not clear how much of it spilled.

Con Ed says it's working with the Coast Guard, the state Department of Environmental Conservation, and other agencies on the cleanup. 

The DEC is investigating the spill.