An international group of researchers is renewing its call for a global ban on the mining and use of asbestos, a known cause of cancer they say is unsafe in any form.
They hope to put pressure on the Canadian government to ban asbestos exports and stop providing financial support to Canadian companies that mine and export the mineral, once used widely to fireproof roofs, insulation and other building materials.
Although asbestos has been banned in 52 countries, annual world production is still more than 2 million metric tonnes, exposing an estimated 125 million people worldwide to asbestos at work, the researchers said on Thursday in the journal Environmental Health Perspectives.
"We have recognized for decades that all forms of asbestos are human carcinogens," said Philip Landrigan of the Mount Sinai School of Medicine and head of the Collegium Ramazzini, an independent group of academic experts in occupational and environmental health that is calling for the ban.
"It is just not possible to work safely with asbestos, especially in developing countries where social controls are weak," Dr. Landrigan said in a telephone interview.
Despite ample studies in people and animals confirming the cancer-causing effects of asbestos, he said sales of the naturally occurring mineral remain strong.
"It's being produced in a small number of countries, including Canada and Russia. It's almost all being used in the third world," Dr. Landrigan said.
The U.S. Environmental Protection Agency, the International Agency for Research on Cancer, and the U.S. National Toxicology Program have declared all forms of asbestos to be proven human carcinogens.
In additional to cancer, asbestos exposure causes asbestosis, a progressive, debilitating lung disease.
In Canada, companies mine chrysotile asbestos, which the asbestos industry says can be used safely under controlled conditions.
But in developing nations, workers often have inadequate protective equipment or engineering controls to provide that kind of safe environment.
"This is a human tragedy that is going to produce many thousands of unnecessary cancers or premature deaths. Most of those are cancers or deaths among people who are least able to protect themselves," Dr. Landrigan said.
His group has sent a letter to Quebec Premier Jean Charest asking him not to extend a $58 million (CAN) loan guarantee to prop up an asbestos mine in his province.
The Canadian Cancer Society and several Canadian public health agencies including the Canadian Public Health Association, the Canadian Medical Association and the National Specialty Society for Community Medicine joined that effort this week.
They estimate that globally, about 90,000 people a year die from disease related to asbestos exposure at work.