For China, it seems, the worst is yet to come.

Asbestos wasn’t used extensively in the country until Deng Xiaoping’s reforms in the late 1970s triggered a surge of development. Given the lag time between exposure to asbestos fibers and the onset of disease, health experts say, the country’s prodigious appetite for the mineral will have lethal consequences into the middle of this century.

Jukka Takala, director of the European Agency for Safety and Health at Work, says that the annual death toll from mesothelioma, lung cancer, and other asbestos-related diseases in China may reach 15,000 by 2035. It’s the price the nation will pay for being the world’s top asbestos consumer and for failing until recently to address health risks associated with asbestos mining and manufacture. In 2007, China used 626,000 metric tons of raw fiber — more than twice that of the next largest consumer, India. It is also the world’s second-largest producer, mining some 280,000 metric tons of the mineral in 2008.

“In the future, China will face a public health crisis triggered by the use of asbestos,” says Li Qiang, executive director of China Labor Watch, which monitors workplace violations. “The guidelines that China’s government has put forward to protect workers do in fact offer workers protection. But the challenge is Chinese officials don’t have any way to effectively implement them. Factories flagrantly fail to respect Chinese law.”  

To be sure, workers in China face a multitude of threats, from toxic chemicals to dangerous industrial machines. They die at a higher per capita rate than workers in any other country, according to the International Labor Organization. But asbestos, a known carcinogen, is particularly lethal, scientists say, and China’s broad embrace of the mineral appears likely to produce an epidemic of occupational disease.

Valued for its heat and fire resistance, asbestos was once widely used worldwide, but it is now banned or restricted by at least 52 countries, including Japan, Singapore, and South Korea. Use of the mineral is banned entirely in the European Union. In the United States — where it is blamed for taking some 200,000 lives and the industry has paid out $70 billion in damages and litigation costs — asbestos use is limited to a handful of products, such as automobile brakes and gaskets.

But in China, asbestos use is booming. More than 400 factories turn out 300 million square metersof asbestos sheeting for roofs and walls each year; other factories make asbestos brake pads, gaskets, and cloth. The industry’s main lobby group, the China Non-Metallic Minerals Industry Association, insists that chrysotile, or white, asbestos, the most widely used form of the mineral, can be handled safely and links from its website to materials from Canada’s Chrysotile Institute and Russia’s Chrysotile Association. The Chinese group denounces what it calls “exaggerations” of the fiber’s deleterious effects and says that those who use phrases such as “time bomb” to warn of looming disease outbreaks are biased. The group failed to respond to multiple interview requests.

The first asbestos mine in China was opened by occupying Japanese forces in the 1940s. Today, virtually all of the asbestos mined in, and imported to, China is of the white, or chrysotile, variety. An estimated 1,000 enterprises employing more than a million people are involved in the production and processing of asbestos, and up to 90 million tons of chrysotile are thought to be lodged beneath the soil in 15 provinces, mostly in the western part of the country. The Aksai Kazakh Autonomous County of Gansu Province alone accounts for half of these reserves and boasts an average annual output of 170,000 tons.

While China has tightened its exposure limit for asbestos over the years, unhealthful conditions in many factories are believed to persist. In 2008, for example, officials in the city of Yuyao, in Zhejiang province, gave unsatisfactory evaluations to most of the 100 or so small asbestos workshops they inspected. That same year, a local journalist visited one of the workshops and found extremely dusty conditions and employees wearing disposable masks, which offer little protection against the tiny, airborne asbestos fibers. Of eight workers who had just had chest X-rays, five showed lung abnormalities.

China has taken steps to try to mitigate the looming health crisis. Brown and blue asbestos — believed by some scientists to be more hazardous than white — have been banned, as has the use of all forms of asbestos in automobile brake linings and other friction products. In Beijing, no asbestos-containing materials may be used in construction, but their use is widespread in new buildings across the rest of China. And in both Hong Kong and on the mainland, the government has committed to pay medical and rehabilitation costs for victims of pneumoconiosis, a class of lung diseases that includes asbestosis.

But for many workers, it’s too late. In a glimpse of what may be the mainland’s future, researchers at the Chinese University of Hong Kong reported in March that the number of mesothelioma cases in the city was still climbing and might not peak until 2014. This doesn’t bode well for the rest of the country considering that asbestos use in Hong Kong, according to the researchers, reached its zenith in the early 1960s and mesothelioma can take 40 or more years to develop.

Unlike some Western nations, China has been slow to embrace asbestos substitutes such as cellulose fiber-reinforced cement. Still, concern over unbridled asbestos use may be building in the region. Last year, Hong Kong hosted a meeting of anti-asbestos activists from around the world. The meeting gave rise to a declaration calling for a ban on all forms of asbestos in Asia. Whether that message was heard in Beijing remains to be seen.