Dexter ? An oil tank explosion early Friday woke up the small southeast Kansas town of Dexter and sent one man to the hospital with minor injuries, authorities said.

The injured man, whose name has not been released, was treated and released from the William Newton Hospital in Winfield, hospital officials said.

The man wasn’t a firefighter, said Winfield fire Capt. Gordon Dippel.

The cause of the fire was being investigated, Dippel said.

Firefighters arrived around 3 a.m. to find 20-foot flames shooting from two large metal oil tanks. The fire was just south of Dexter.

One of the tanks contained about 1,000 barrels of oil, while another had only about 30 barrels.

“My wife woke me up,” said William Speer, who works as the pumper of the oil tank unit owned by Larry H. Hale. “She yelled, ‘Get up. Something just blew up.’

“It woke up the whole town.”

The tanks are part of what is called an oil tank battery. A pump jack draws the crude oil and salt water from the ground. From there, the substance goes through a separator that divides the water from the oil. The oil then goes into the storage tank.

“We’ve had in my career numerous tank battery explosions,” Dippel said. “It’s not uncommon.”

The fire was extinguished by about 5 a.m.