When a bomb went off in New York, these officers raced toward it (VIDEO)

New York (CNN) Dan Sendrowski and John Campanella were turning onto a busy Manhattan street in their patrol car when the explosion went off.

The New York Police Department officers didn’t know what was going on, but they knew they needed to help. They raced toward the blast.
“The flash was really fast and then just a lot of smoke,” Sendrowski, 34, said. “When we got to the corner there was a lot of people kind of just waving their arms and just kind of pointing down the block.”

They saw a mangled dumpster flung across 23rd Street and later learned it was launched by a device made of shrapnel and pressure-cooker bombs. Officials would eventually call the explosion an “act of terror.”

Amid scorched trees, shattered glass and worries there could be more explosives in its wake, both officers quickly urged bystanders to leave the area.
“I can’t imagine even what they thought of. We saw it too but they were at ground zero, they were right there,” Campanella, 25, said.
The blast in New York’s Chelsea neighborhood injured 29 people on September 17. But in the moment, Campanella said they didn’t know whether people had been killed.

“I just saw blood on their clothes. They were just hysterical. I tried to calm them down and say help is on the way, and that was pretty much all I could do,” he said.

At that point, the two men began breathing in smoke from the explosion. Campanella turned to Sendrowski, telling him to hang back. “We didn’t know what kind of chemical agents we were dealing with,” Campanella said.

Read more about these officers who went beyond the call of duty [HERE].