FENGXIANG COUNTY, China (CNN) -- At the Fengxiang County Hospital in Shaanxi Province, children are sleeping two to a bed. Cots line the hallways and hospital beds crowd offices to accommodate the ceaseless flow of new patients. In the last two weeks, so many children have been diagnosed with lead poisoning that there's barely enough room for everyone.
Villagers who live near the plant say almost all children have excessive lead levels in their blood.
Their parents are outraged and confused.
"My toddler is a year and nine months old," says Pen Xiaoxia holding her daughter in the hospital ward. "Her hair isn't growing and she's sick all the time."
"My older daughter's nails stopped growing, and her hands are bigger than normal," Pen told CNN. "She doesn't listen to me and she's very rebellious. She can't remember what I told her and she always has a headache."
Holding their children in one arm, every parent in the hospital clutched a thin white sheet of paper in the other, showing the results of their child's blood tests.
In the room next door, nine-year-old Lei Xinyuan was said to have one of the most serious cases in the hospital. She looked like she could be six or seven years old.
"She stopped growing last year," says her father, Mr. Lei. Watch children await treatment for lead poisoning »
In total, more than 850 children in the area have tested positive for excessive levels of lead in their blood, according to government officials. All of them live in Madaokou, Sunjianantou, and other villages clustered around the Dongling Lead and Zinc Smelting Plant. Angry parents attacked the plant this week and police were called in to restore order.
After repeated phone calls, company officials said they could not comment and referred all questions to the county government.
County officials said they have ordered the plant to shut down within days.
"We are planning to relocate all residents as fast as possible," says He Hongnian, Vice Governor of Fengxiang County.
State-run media reports the relocation could take as long as two years. Environmentalists say the area is already polluted and extremely dangerous. Lead poisoning can continue to occur via contaminated air, water, soil or food, especially crops grown in tainted areas.
Doctors say chronic exposure can lead to life-long consequences, even death.
"[With] children in international settings, you see a lot more fatalities from lead poisoning," says Dr. Mary Jean Brown with the Atlanta-based Centers for Disease Control.
"Children can become mentally retarded, and even children who don't have serious symptoms, you might look at them and not even know they've had lead poisoning," Brown adds. "Those children will later have problems in school, they'll have attentional deficits, they may have behavioral problems that will make it difficult for them to learn how to control themselves and their tempers."
China has faced problems with pollution as the country has moved forward with industrial development and economic growth. The government has committed to clean-up measures. But concerns remain.
Chinese authorities closed a second metal smelter this month after more than 1,300 children were found to have elevated levels of lead in their blood, according to state-run media. That case involved children living near a manganese plant near Wugang, in Hunan Province, Xinhua news agency said. Angry parents there also protested.
Back in Shaanxi province, on the streets of Sunjianantou village, which is situated right next to the Dongling plant, parents clamored to discuss their children's test results, scribbled onto white pieces of official paper.
Only the most serious cases of lead poisoning are being treated at the county hospital, all expenses paid by the government.
Zhang Juntao is the father of two children who both tested positive for abnormal blood-lead levels, but not high enough to go to the hospital.
"They always bite their fingers. Sometimes they even bite other kids when they get mad," Zhang says. "I've been reading in books that those are symptoms of lead poisoning."
He says his four-year-old son, Zhang Yicong, is two years behind in school and is underperforming in math. His four-year-old daughter, Zhang Jia, has chronic stomach aches.
Their father says he feels helpless, like he can't protect his children from being poisoned in their own home.
"If I had the means, I wouldn't allow my children to go to school here," he says. "The only way is to leave this place, but we can't afford it."