Harbin, China ? China’s leaders sent a team to investigate a chemical plant accident that poisoned a major river, saying officials responsible will be punished as the 3.8 million residents of this northeastern city endured a fourth frigid day without running water today.

Hundreds of villagers were being evacuated near Harbin on the Songhua River as toxic benzene flowed past, while a Russian city downstream braced for its arrival. In China’s southwest, about 6,000 people reportedly were evacuated following a second chemical plant explosion, raising fears of a new poisoning disaster.

In Harbin, a line of about 500 people stretching for 100 yards waited in windy, subzero weather on Friday in a working class district on the city’s east side for water to come by truck. When a truck with a tank on its bed arrived, residents rushed to fill tea kettles, buckets and basins.

The government earlier said the 50-mile-long flow of benzene was expected to pass Harbin early today. But news reports warned the public that water service would not resume until late Sunday night in order to make sure supplies are safe.

The team of investigators sent to Harbin on Friday included disciplinary officials, which “indicates punishments of irresponsible acts are on the way,” the official Xinhua News Agency reported. But Chinese leaders have come to rely on such hand-picked teams to investigate disasters, tacitly admitting they cannot trust information from local officials.