BEIJING – China’s largest reported oil spill emptied beaches along the Yellow Sea as its size doubled Wednesday, while cleanup efforts included straw mats and frazzled workers with little more than rubber gloves.

An official warned the spill posed a “severe threat” to sea life and water quality as China’s latest environmental crisis spread off the shores of Dalian, once named China’s most livable city.

One cleanup worker has drowned, his body coated in crude.

“I’ve been to a few bays today and discovered they were almost entirely covered with dark oil,” said Zhong Yu with the environmental group Greenpeace China, who spent the day on a boat inspecting the spill.

“The oil is half-solid and half liquid and is as sticky as asphalt,” she said by telephone.

The oil had spread over 165 square miles in the five days since a pipeline at the busy northeastern port exploded, hurting oil shipments from part of China’s strategic oil reserves to the rest of the country. Shipments remained reduced Wednesday.

State media has said no more oil is leaking into the sea, but the total amount of oil spilled is not yet clear.

Greenpeace China released photos Wednesday of inky beaches and of straw mats about 21 square feet in size scattered on the sea, meant to absorb the oil.

Fishing in the waters around Dalian has been banned through the end of August, the state-run Xinhua News Agency reported.

“The oil spill will pose a severe threat to marine animals, and water quality, and the sea birds,” Huang Yong, deputy bureau chief for the city’s Maritime Safety Administration, told Dragon TV.

A 25-year-old firefighter, Zhang Liang, drowned Tuesday when a wave threw him from a vessel, Xinhua reported.

Officials, oil company workers and volunteers were turning out by the hundreds to clean blackened beaches. “We don’t have proper oil cleanup materials, so our workers are wearing rubber gloves and using chopsticks,” an official told the Beijing Youth Daily newspaper, in apparent exasperation.