BANGKOK >> Black waves of crude oil washed up on a beach at a popular tourist island in Thailand’s eastern sea despite continuous attempts to clean up the oil up over the weekend after it leaked from a pipeline, officials said today.

Tourists on Samet island were warned to stay away from the beach marred by inky globs as hundreds of workers in white jumpsuits labored to scrape the sand clean and remove the oil from the water.

About 50 tons of oil spilled into the sea off Rayong province Saturday morning after a leak sprung in a pipeline operated by PTT Global Chemical Plc, a subsidiary of state-owned oil and gas company PTT Plc.

Streaks of crude oil about 984 feet wide have marred the shore of Prao Bay on Samet Island, one of the most popular beach destinations among Thai and foreign tourists in the Gulf of Thailand, Rayong’s deputy provincial governor Supeepat Chongpanish said on Monday.

He said authorities have closed down the bay as 300 workers are working to remove the oil from the white beach and from the waters.

“The top priorities right now are to get rid of the oil on the sand and the seawaters, and to make sure the spill doesn’t spread to other shores,” Supeepat said. “This is a very beautiful, white, sandy beach, so we want to make the spill go away as soon as possible.”

Known for its quieter scene and serene beach, Prao Bay is blackened by waves of oil slicks that lashed at the shore.

“The black waves started rolling in since last night and by the morning the beach was all tainted with oil,” Kevin Wikul, the assistant front desk officer of a resort in Prao Bay, told The Associated Press in a telephone interview. “We have advised our guests against going near the beach and some of them have asked for early check-outs.”

The nearby area has been declared a disaster zone by provincial authorities, and those affected by the spill will receive immediate assistance.

The company said it detected the leak when the crude oil from a tanker moored offshore was being transferred to the pipeline, 11 miles away from delivery at the refinery in Map Ta Phut, one of the largest industrial estates in Southeast Asia.

The company said in a statement Sunday that it had flown in an oil spill management experts and a plane from Singapore to get rid of the crude oil. The Thai Navy vessels also joined the cleanup efforts.

Authorities said it would take some time to assess the environmental damage the spill has caused.

“The spill is definitely having an impact on the environment, but we have not detected any deaths of marine animals yet at this point,” said Rayong provincial governor Wichit Chatphaisit. “PTT will have to take responsibility about the damage this has caused.”

He said the pollution control department officials had also expressed concern about the effect from the chemical used to clean up the spill.

The refinery on the shore was not affected by the leak.

In 2009, another PTT subsidiary was involved in the Montara oil spill, one of the Australia’s worst oil disasters, in the Timor Sea off western Australia.