Roughly 1,000 gallons of oil spilled out of Con Edison equipment and into the Bronx River last week, and state officials said on Monday they were still scrambling to clean up the mess.

Alfonso Quiroz, a spokesperson for the utility company, said the leak originated at one of its transmission feeder lines in Yonkers on April 1. He said the substance was a “non-hazardous insulating fluid, non-PCB and non-Benzene, similar to mineral oil,” and that it flowed into a storm drain that pours into the river at Nereid Avenue.

Con Edison and state officials deployed seven absorbent devices, known as booms, along the river, from McLean Avenue in Yonkers down to Fordham Road in the Bronx, including an area north of the New York Botanical Garden.

“The booms should prevent any significant amount of fluid traveling farther south,” Quiroz said.

Elena Conte, interim executive director of environmental nonprofit Bronx River Alliance, said crews took a “very aggressive” approach to cleaning up the river. But she said she was upset by how little the public knew about the spill, calling it a “serious and problematic” incident.

“The information to the public was not as quick or as clear as we would have liked,” Conte said, adding the public wasn’t notified about the spill until her organization shared the news days afterwards.

Conte said the oil was “not the most toxic that could be in the river” but noted her group remained concerned about the spill’s impact on the river, its ecology and wildlife.

The state Department of Environmental Conservation is overseeing the cleanup. Its efforts have been delayed by recent storms in the area, including one last Wednesday, according to officials.

Oil spills are “not unprecedented” in the Bronx River, Conte said. Last week’s is smaller than another in 2015, when a Con Edison cable pipe leaked 2,200 gallons of dielectric fluid and insulating oil into the river.