Cancers caused by inhaling asbestos dust will kill up to 12,000 New Zealanders, mostly building workers, according to a study.
"The asbestos cancer epidemic has started," two Auckland Medical School researchers reported in an article published last week in the New Zealand Medical Journal.
Based on their calculations, the researchers said, up to 4,000 people will die from malignant mesothelioma and another 8,000 from asbestos-related lung cancer.
Mesothelioma is a cancerous tumor that usually grows in the pleura, the membrane surrounding the lungs, after microscopic needles of asbestos have "migrated" through the lung tissue.
The disease can lie unnoticed for 30 years after exposure, and then cause only vague symptoms, including breathlessness and chest pain. It is incurable and usually kills within a year of diagnosis.
The researchers tracked imports of crude asbestos, which peaked at 12,500 tons in 1974 and dropped to zero by 1992, suggesting the epidemic could peak in the next 10 to 15 years.
But they expect that an ongoing "tail" of post-epidemic cases resulting from the asbestos already installed in offices, factories and homes will exceed the pre-epidemic background rate.
The New Zealand Occupational Safety and Health (OSH) service said asbestos should cause problems in homes only if it is crumbling or disturbed, such as by floor sanding after the removal of certain vinyl floor coverings, some of which had asbestos backings.
At least 13,000 people have reported workplace asbestos exposure in New Zealand.
Since 1992, 923 cases of asbestos-related disease have been reported to an OSH register, 30 percent of them cancer, although many cases are thought to go unreported.
Ninety percent of mesothelioma victims are men, most of them from the building trades.
by Virginia Sutcliffe