The leaking 100-gallon tank that washed ashore on Kauai last month contained small amounts of kerosene, a fuel that is toxic to marine life but which floats and eventually evaporates.

The Garden Island, quoting the state Department of Health, said the punctured tank contained about 3 gallons of liquid, a combination of sea water and residual kerosene.

“The translation of the Chinese writing (on its side) was ‘lantern oil,'” said Health Department spokeswoman Janice Okubo.

It is unknown if the tank is debris from the March 2011 Japanese tsunami.

The aluminum tank washed ashore Aug. 28 at Waipouli Beach near the Courtyard by Marriott Kauai.

Elizabeth Galvez of the DOH’s Hazard Evaluation and Emergency Response Office said the container’s contents were removed by DOH and will be properly disposed of. The tank was removed from the beach Aug. 30, rinsed out and taken to a recycling facility on Kauai, she said.

Carl Berg, the Japanese tsunami marine debris coordinator for Surfrider Kauai, said the tank was likely kept aboard a large ship or on dock.

“They use that for cooking stoves on ships,” he said. “That would be my guess.”

The concentration of barnacles and seaweed indicated the tank had not been full of liquid recently.

“It wasn’t floating submerged,” Berg said. “It was two-thirds of the way out of the water.”