In a rare public admission of failure, China's Communist government fired the country's environmental protection chief Friday, saying his agency underestimated the impact of a massive chemical spill and mishandled the response to a disaster that poisoned the water supply of millions of people.

The dismissal of Xie Zhenhua, director of the State Environmental Protection Administration, followed nearly three weeks of conflicting and often misleading government statements about a toxic spill that polluted the Songhua River in China's northeast. The spill forced the shutdown of running water in Harbin, a city of 3.8 million, and continues to threaten residents downstream in neighboring Russia.

Journalists and Communist Party sources said the decision came after a prolonged internal debate among China's top leaders over who should take the blame for the catastrophe, which was triggered by an explosion Nov. 13 at a state-owned petrochemical plant in Jilin province.

The sources said senior company and provincial officials who sought to hide the toxic spill from the public were also in danger of losing their jobs as the party struggles to repair the damage done to its reputation.

Xie, who had served as head of the environmental agency since 1993, is the first cabinet minister to be fired for reasons other than corruption since the spring of 2003, when the party dismissed the health minister and the mayor of Beijing after admitting its coverup of an outbreak of SARS, severe acute respiratory syndrome.

The official New China News Agency announced the dismissal of Xie shortly after 6 p.m., saying the party and the central government had accepted his resignation and appointed Zhou Shengxian, director of the State Forestry Administration, in his place.

A report on the agency's English-language service described Xie as the "highest-ranking official to be removed from office for an environmental incident" in China and said his dismissal "shows the improvement of China's political system."

"Chinese authorities are increasingly aware of the danger of seeking economic development at the cost of the environment, as well as the importance of boosting government accountability," the article said. It reminded readers of the dismissal of the officials during the SARS crisis and of the general manager of China's largest oil company in 2004 after an explosion killed 243 people.

Coverage of Xie's dismissal in the domestic news media was more conservative. In a report on the evening news laced with party jargon, state television said the party's Central Committee and the State Council, the Chinese cabinet, had approved a communique saying the environmental protection agency "did not pay enough attention" to the toxic spill and "underestimated the grave consequences that were possible."

The report said President Hu Jintao and Premier Wen Jiabao issued "a series of important instructions" ordering officials to improve industrial safety and strengthen the government's response to public emergencies. It also repeated an official pledge to "investigate the cause of the explosion incident and the major water pollution incident, and strictly punish the responsible personnel."

But the report made no mention of the government's failure to immediately disclose that 100 tons of benzene and other toxic pollutants had poured into the Songhua River after the explosion at the petrochemical plant, which is owned by one of the country's most influential oil companies, China National Petroleum Corp.

Company managers and local officials in Jilin publicly denied for 10 days that any pollution had resulted from the blast. Then, as a 50-mile slick of toxic chemicals approached Harbin, the provincial capital of Heilongjiang province about 600 miles northeast of Beijing, officials there shut down the city's water supply for five days but said at first they were doing so to conduct repairs.

City officials disclosed the truth about the contaminated water about 12 hours later, in the middle of the night, after receiving permission from Beijing, according to state media. The conflicting explanations fueled public confusion and prompted a rush by residents to leave the city, as well as panic buying of water bottles and other supplies.

The provincial governor, Zhang Zuoji, later acknowledged telling a "lie with good intentions" because he was worried about causing a panic, hurting the local economy and contradicting the denials of the officials upstream in Jilin.

At a news conference Nov. 24, one of Xie's deputies defended the government response to the spill, saying Jilin officials acted properly. But in comments reported in state media Friday, another of Xie's deputies criticized the Jilin officials for "poor work" and accused them of waiting four days before providing the environmental protection agency with "any account of the accident."

The deputy, Wang Yuqing, said the delay meant "losing the best opportunity" to control the spill, according to the China Youth Daily and the China Daily.

It remains unclear when Xie was informed of the toxic spill and what he told the party's top leaders about it. Some journalists described him as a convenient scapegoat who is being sacrificed by the party leadership in an attempt to distance itself from the disaster.

A government environmental agency worker takes a sample from the contaminated Songhua River.