Huixian County is in the southeast of Gansu province and has rich deposits of lead, zinc, iron, mercury, sulphur, etc.  There are 3 large deposits of lead and zinc and 1.05 million tons of metal reserves. With this advantage, Huixian Nonferrous Metals Smelting Co., Ltd. was established in 1995 and in operation one year later (1996) and quickly became the leading enterprise for smelting of lead metal. The tax paid by more than 10 lead-zinc mines and companies in the county have accounted for more than 60% of the county’s finances. 
While the lead industry has brought economic benefits to the county, the environment has degraded. Lead emission from the Huixian Nonferrous Metals Smelting Co., Ltd was 200 tons per year. The lead quickly fell to the ground due to its high density and polluted the farmland. During that time, the local peasants turned into “black men” after harvesting corns. No one would like to buy the vegetables grown on the land around the company.  A villager said that during the day, a smelly smoke came out of the smelting place. 
The distance between the Shuiyang Township Primary School and the company was less than 500 meters. According to a teacher, some students often had symptoms such as stomachache, vomiting, memory loss, and inattention. The blood lead levels (BLLs) of the students who had undergone laboratory tests all exceeded the normal standard (100 ug/L).  The teeth of some children in the village were incomplete and black, which made the 6 or 7-year old children look like 60 or 70 years old.  According to The China Environment Yearbook, “Children absorb 42 to 53 percent of the lead they ingest, about five times the adult rate. Making matters worse, they expel lead from their bodies at only about 30 percent of the adult rate.”  Lead poisoning can cause serious harm to children's growth and development. It affects the body's absorption of iron, zinc, calcium and other elements. When these elements are lacking, the absorption of lead by the body will be enhanced, which becomes a vicious circle for the young victims. 
Although the pollution (especially from lead) was serious, the problem has been concealed many times. In the heavily polluted Xinsi Village, an incident about “dead soybeans” happened in March 2006. About 1600-mu (around 107 ha) of soybean cultivation in the village almost failed, but it did not attract enough attention from the local government and the incident was ended with some compensation. After a hospital in Xi'an city of the neighbouring Shaanxi Province found the first cases of children with excessive BLLs from Huixian County, the local hospital of Huixian County inspected the villagers with the result of “all normal”. When many villagers were found to have excessive BLLs and asked the polluting enterprise to be closed, they got the answer that the company had completed procedures and the certification of the environmental protection department. "The so-called environmental pollution does not exist."  This action of trying to hide the lead problem caused distrust among local villagers to the government of Huixian County, as well as the medical experts sent by the province and municipality, and even the journalists from Gansu province.  With more persons found to have excessive BBLs, on August 27, 2006, people gathered to petition Huixian Nonferrous Metals Smelting Co., Ltd. because they heard that the company would move the lead material to another place and they were afraid the evidence would be ruined.  The tension that had accumulated about the lead pollution during 10 years (from 1996 till 2006) broke out.
As of September 7, it was reported by the People’s Daily that 877 people got blood test in the Xijing hospital (in Xi’an city, the capital of Shaanxi Province), and the number of people with excessive BLLs was 368, including 149 children under the age of 14. 
According to the Gansu Health Department (as the "Health Commission of Gansu Province" since March 2018), as of October 9 in the same year, 954 children in Huixian County were confirmed with excessive BLLs.  While according to the news of 2010, which referred to a report from Huixian County, there were 1,131 people in total with excessive BLLs, of which over a half were children.  Due to the different sources and criteria used in the statistics of affected people, it is difficult to get the accurate number of victims.
The incident not only attracted the attention from media, but also the Central Government and the CPC Gansu Provincial Committee. The provincial government attached great importance to the incident. State Councillor Chen Zhili, Gansu Provincial Party Committee Secretary and other relevant officials successively made important instructions and endorsements, requiring the relevant departments to investigate and handle the treatment for high-lead patients.
On September 8, 2006, the National Environmental Protection Administration and the Gansu Provincial Environmental Protection Bureau formed a joint team to conduct an investigation. The administration indicated that since the commissioning of the Huixian Nonferrous Metals Smelting Co., Ltd. in 1996, the company has used a backward production process and equipment which were abandoned by the government. The facilities of environmental protection have not been established in accordance with the requirements of the environmental assessment, and there was a long-term problem of discharging excessive pollutants. The soil within 400 meters of the company has been contaminated. According to the joint investigation team and the National Environmental Protection Administration (as Ministry of Ecology and Environment since March 2018), if the company wanted to resume production, it was required to move to a place far away from residents and water sources, and to comply with national environmental and industrial policies. 
On September 9, the sintering pot was dismantled and eliminated. Huixian Nonferrous Metals Smelting Co., Ltd. was closed.  In the same month, more than 600 lead pollution victims of Huixian County sued a civil infringement case of the lead pollution in the People's Court of Huixian County. As of June 30, 2011, the number of plaintiffs increased to 1,113. According to the mediation plan, polluting enterprise would pay more than 90 million (CNY) compensation to the victims. Among over 4,000 people registered in the court, more than 1,800 people with excessive BLLs would receive compensation; the polluting enterprise was willing to pay another 1,500 adults who have not had excessive BBLs CNY 300 (44.64 USD dollars)/person. Besides, the enterprise would apologise to the public with a letter. On May 2007, the chairman of the company was suspected and transferred to the judicial authorities. The other 19 responsible persons for the incident were dismissed or severely warned by the party .