A botched oil delivery spilled heaps of fuel across a block of Manhattan’s First Avenue on Monday, forcing emergency crews to direct traffic around the scene in a move that worsened gridlock caused by the ongoing United Nations General Assembly on the East Side.

Firefighters and hazmat crews responded to the spill near East 30th Street around 11:45 a.m., according to a fire department spokesperson. A truck owned by the company, Approved Oil, had a hose connected to a building on the block before its haul spilled all over the roadway, bystanders said.

City officials said the official cause of the incident remained under investigation. Frank Millo, who was on the block when oil from the truck started spewing all over the pavement, said a man riding an electric bicycle ran into the hose, which was laid over the street’s bike lane, springing the leak.

“That was when the oil started spilling,” said Millo, 70. “Very little at first, then it started to build up.”

The oil briefly turned the stretch of First Avenue into a scene out of the video game Mario Kart before emergency crews closed the block to traffic. Diellza Krasniqi said a man riding a bicycle slipped and crashed when he ran over the slick.

“He got up, he was screaming, saying that it was oil, and he was covered in oil.“ Krasniqi said the man scolded workers from the building receiving the oil delivery before taking off. “Some of the passerbyers were getting into the bike lane and trying to stop people from riding in the bike lane.”

The truck from the company Approved Oil was making a delivery on First Avenue when a leak spilled fuel all over the busy street.

The oil was being delivered to the residential Kips Bay Towers. Crews from the building helped clean up oil from the spill that reached its property, but declined to comment on the incident. A representative for Approved Oil said a manager who could speak to the spill was not available.

The street was reopened to traffic by around 2 p.m. The odor of fuel lingered in the air while sanitation workers spread sand on the roadway to soak up the remaining oil.

“I smell oil,” said Ronnie Koten, 75. “There’s still oil on the streets, but the fire department is doing a great job trying to clean it up. I assume it will take a few more hours and hopefully it'll be clear tomorrow.”

The oil spill came on the second day of New York City’s annual Climate Week, where people from around the world gather to push to move the global economy away from fossil fuels.

Officials with the state environmental conservation agency were on the scene to investigate the cause of the spill.