Chinese authorities are worried that respiratory illnesses rage unabated among migrant workers.
"Work-related disease has still not been controlled effectively," conceded Minister of Health Chen Zhujoined Chen and pointed to the accumulation of more than 700,000 such cases since the end of 2008. He was speaking at a conference in Beijing on Friday.
The number of laborers suffering from occupational diseases may be far higher than the recorded level because relatively few migrant workers get regular health checks.
"The number of new cases of work-related illnesses will keep climbing," Chen warned.
The minister revealed that some illnesses, such as pneumoconiosis - the so-called black lung disease that affects many miners - are becoming more prevalent. And he said more respiratory diseases are being diagnosed in younger people than before.
The country's 250 million migrant workers, who mostly work in small- and medium-sized enterprises, often have not signed contracts, move frequently and are at high risk of contracting an occupational disease, Chen said.
But the risk of pneumoconiosis is already prompting some miners to take precautions.
"The dust invades the body day by day," said Deng Qixiang, a veteran at a coalmine company in Beijing who insists on wearing a mask at work.
"The patient's lung is as hard as a stone."
Pneumoconiosis is caused by long exposure to mineral or metallic dust and emergent poisoning at work.
There are nearly 640,000 pneumoconiosis patients in total in the country, with 10,000 new cases reported each year.
Yang Yuanyuan, vice-minister of the State Administration of Work Safety, the country's top safety watchdog, said many migrant workers are injured and killed in workplace incidents each year.
About 8 out of 10 accidents took place in either small coalmines, chemical factories, fireworks workshops or construction sites, where the majority of workers are migrants.
For example, of 1,001 migrants working at a gold mine in coastal Hainan province, about 600 people received a check up. Of them, 225 were found to be suffering from pneumoconiosis. Some 14 people died and many lost their ability to work, according to the administration's research in Mashan County in Guangxi Province this year.
Zhang Mingqi, vice-chairman of the All China Federation of Trade Unions, urged employers to make greater strides in the prevention and treatment of work-related illnesses, and abide by the labor contract.
And the health minister urged local governments to tighten the eligibility of projects by considering their impact on workers' health. He also called for efforts to be made to strengthen the monitoring mechanism and establish more occupational disease prevention and treatment centers, China Daily reported.