(Adds details of suicide attempt, police and mayor)
BEIJING, Aug 17 (Reuters) - Chinese protesters on Monday broke into a smelting works they blame for the lead poisoning of hundreds of children, smashing trucks and tearing down fences, state news agency Xinhua said.
More than 600 children living near the Dongling metal smelter, in northwest Shaanxi province, have dangerous amounts of the heavy metal in their blood and 154 are so sick they have been admitted to hospital, the report added.
Protests against pollution are increasingly common in China, although the police normally try and nip them in the bud before they become violent. In other cases, officials show up and mollify residents with promises of financial or other aid.
Monday's protests began after news spread around villagers that the poisoning had sparked a suicide attempt by one 19-year-old student, Xinhua reported.
The student drank pesticide after her parents refused to pay for her to take a blood test, Xinhua said.
The government is only offering free tests to children under 14, and there has been no investigation into whether adults might be affected by lead from the smelter, the report added.
Around 100 policemen had been mobilised by midday, and the mayor of nearby Baoji city, who heads a newly formed pollution control team, arrived to ask protesters for restraint.
By early afternoon, most protesters had returned home, Xinhua said.
The lead poisoning scandal emerged last week, after worried parents took their children for medical tests.
All the affected families live near the Changqing industrial park in Shaanxi province. The county government was supposed to help relocate villagers living close by in 2006, but the plan is running far behind schedule.
The 100,000-tonne lead and zinc plant suspected of causing the poisoning is run by China's fourth-biggest zinc producer Dongling Group.
A company source told Reuters it had been shut for repairs since late July and it was unclear when production would resume. Xinhua said operations were suspended on Aug. 6.
LAX SAFETY STANDARDS
China's pollution and lax product safety standards have long been a source of tension and unrest, particularly when residents of pollution hotspots -- dubbed "cancer villages" because of high disease rates -- feel they are being ignored. [ID:nPEK92601]
A child who swallows large amounts of lead may develop anaemia, muscle weakness and brain damage. Where poisoning occurs, it is usually gradual.
Cases involving children are particularly sensitive in a country where many families have only one son or daughter. China was shaken last year by a tainted milk scandal, which killed at least six children. [ID:nPEK199017]
Dongling is still running two other zinc lines in a separate area of Shaanxi province, with combined annual capacity of 150,000 tonnes.
A local environmental protection official said tests showed waste discharge from the lead smelter, and nearby ground and surface water, and soil, met national standards, Xinhua reported.
But there are high levels of the heavy metal in the air near the factory.
"Lead content in the air along the main routes near the plant is 6.3 times that of monitoring sites 350 metres from the roads," said Han Qinyou, head of the Baoji Municipal Environmental Protection Monitoring Station.
Additional reporting by Polly Yam in Hong Kong; Editing by Dean Yates
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