(CNN) -- Two people were killed and three others were in critical condition Saturday when a truck carrying fireworks on North Carolina's Outer Banks exploded, officials said.
Smoke from the explosion of a truck carrying fireworks rises over Ocracoke Island, North Carolina, Saturday.
Jamie Tunnell, Hyde County spokeswoman, said the fireworks were to be used for the annual Fourth of July show on Ocracoke Island, and the five people were members of the crew setting up the display.
The truck exploded at the Ocracoke Island docks.
One person was killed at the scene, while another died at a hospital from injuries sustained in the blast, Tunnell said.
Emergency crews and firefighters arrived. Tunnell said two volunteer firefighters were being treated for smoke inhalation and exhaustion.
Joseph Chestnut, 16, was working at the Ride the Wind kayak-rental stand in Ocracoke when he heard the explosion across the harbor. He thought a home under construction had collapsed, he told CNN's iReport. iReport.com: Smoke rises from explosion site
"I saw all these fireworks blowing up," he said. "They were low, and I knew that something was wrong." Watch images from the scene »
"It was just really scary. There's never been an accident like that before that I've seen here," Chestnut added.
The Hatteras Island ferry service was temporarily suspended, but had reopened by midday, and Highway 12 was clear, she said. The island, which is part of the Cape Hatteras National Seashore, can be reached only by ferry, private boat or plane.
The FBI and the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives were going to investigate on Saturday, she said.