To three-year-old Liu Zhi, the chlorine explosion near his home in southwest China's Chongqing municipality meant a sudden heavy bang and great terror.

He is also hoping to see his grandmother, who was separated from the family during a hurried evacuation. The little boy is nowstaying with his parents at a middle school, which has been turnedto a relief camp.

The chlorine leak and explosion at the Tianyuan Chemical Industry Plant in Chongqing Friday afternoon left nine dead or missing and three injured and forced over 150,000 people to evacuate.

Liu Zhi may get to see his grandmother soon as authorities and experts have worked out a plan to explode the three remaining chlorine tanks at the accident site Sunday morning, which means risks of possible spontaneous blasts will eventually be removed.

In Hualongqiao, a district affected by the polluted air, some 12,000 people evacuated Friday have been sent home. However, some 20,000 people from the nucleus area of the accident have to spent their second night at temporary lodging sites Saturday evening.

They cannot return home until the remaining chlorine tanks are exploded Sunday morning.

Shi Daping, a leading official of Jiangbei District, the nucleus area of the accident, said the government will make sure that all 20,000 evacuees have lodging and meals arranged.

The accident did not affect water supply greatly, according to the municipal water group.

After the accident occurred, an emergency water quality projectwas started up quickly. The water group has set water monitoring spots at five water supply sites. The half-an-hour examination of water quality showed that water was not polluted and can be used as drinking water, said the group.

Meanwhile, larger water users were notified in time to conservewater for future use.

Air quality had also returned to normal levels by Saturday morning.

The municipal environment monitoring center has set up 11 air quality stations in the major downtown districts, five of which are around the chemical plant.

By 5 a.m. Saturday, the chlorine quantity in the air monitored by the center was back to normal, said Wang Lijun, deputy directorof the bureau.

Firemen had been spraying sodium hydroxide liquid at the site since the explosion happened on Friday to neutralize the chlorine gas, said the firemen director Wang Qinlin.

Chinese Premier Wen Jiabao and other high-ranking officials have ordered effective relief and investigation work, stressing all possible risks must be considered and removed.

Officials and experts directing the rescue work decided on the explosion plan Saturday evening after they studied the feasibilityof four proposals on how to deal with the remaining toxic gas.

Experts said the gas tanks will be exploded by shooting from a distance.

They said there is little chance that the remaining gas will blow up spontaneously Saturday night while being let out.

However, firemen have been stationed near the site in case of accidental blasts.

It is expected that the five tons of gas in the tanks will be reduced after a night's natural release and a low amount of gas content will keep possible risks at a minimum.

Source: Xinhua