Two women were killed and another woman and two men were hospitalized with burns after a pleasure boat caught fire and exploded at a marina in Long Beach, California, authorities said.

The blaze was reported around 5:15 p.m. Saturday on a 35-foot powerboat at a fuel dock in Alamitos Bay, the Long Beach Fire Department said.

Cory Valdes was on another boat nearby when he heard the explosion and then saw flames consume the vessel.

WISCONSIN TEEN CHARGED WITH TRIGGERING BONFIRE EXPLOSION THAT BURNED AT LEAST 17 PEOPLE

"It was so loud, it shook us," he told the Long Beach Press-Telegram. "It went up so fast — you are talking ten, fifteen seconds and it was fully engulfed."

One man was quickly able to get off the burning boat and onto the dock, Valdes recalled, while the other man and a woman jumped into the water.

Valdes and others grabbed a hose to help fight the flames until a a fire boat arrived with a water cannon. Firefighters initially struggled to find the two remaining women on the boat, Valdes said.

"You know there are the other two on board, you are hearing yelling, you think you are hearing screaming — it was just a poor, sad situation," said Valdes, who's retired from the U.S. Coast Guard and is a regular at the marina.

ONE DRIVER SERIOUSLY BURNED IN WISCONSIN FAIR DEMOLITION DERBY FIRE

The fire sent up a black plume of smoke that could be seen and smelled from throughout the area that is about 30 miles south of downtown Los Angeles.

All of those killed and injured were in their 60s, Fire Capt. Jake Heflin told the newspaper. Their identities were not immediately released.

The cause of the fire was under investigation Sunday.

The wreckage of the boat was towed to an isolation dock to prevent environmental damage from leaking fuel, Heflin said.