Engineers have declared the second attempt to cap a gas leak in southwest China, which had lasted six days and forced an evacuation of 12,000 people, an initial success.

Fires that had blazed around the gas well in Xuanhan County, Sichuan Province, were almost put out, according to He Shenghou, deputy general engineer of China Petrochemical Corporation, owner of the well.

"The capping operation is an initial success," said He.

The leak occurred last Thursday at the Qingxi No. 1 Gas Well in Qingxi Town, northeastern Sichuan, during drilling. More than 12,000 residents nearby were evacuated after the leak.

The first attempt to cap the well was carried out on Monday but failed.

Most of the 12,000 residents have returned home after local environmental protection authorities said no toxic chemicals were detected in the air. About 700 of them are yet to return because their houses are within 500 meters (1,600 feet) of the well.

No casualties have been reported in the gas leak, according to local officials.

Xuanhan County, about 500 kilometers to the northeast of Chengdu, capital of Sichuan, is one of China's major natural gas bases.

A gas leak three years ago in the neighboring Chongqing Municipality killed 198 people and caused more than 9,000 people to be treated in hospital for gas poisoning.

(Xinhua News Agency December 28, 2006)