Asbestos dangers depend on colour

Press, 17 April 1980, Page 22

Asbestos dangers depend on colour

brown, white or, blue, the risks differ with the type. ... The assistant director (dccupatidnal health), of the Division of Public Health (Dr John Stoke) says blue asbestos is the most dangerous.

“The asbestos regulations, which came into effect last year, have prevented the use of blue asbestos and no work can be done with it without approval from the ’ Depart.'ments of Health and ■Labour,” he said. < ‘‘The Environmental ■"Dust Laboratory has been .'established to provide the facilities to 'identify ' asbestos and t measure its concentration (in air samples, taken from "areas where it is used or being removed.” >£ A scientist working at ' the laboratory, Dr Euan Nicdl, found that some people were not keen on

working in buildings'. that had asbestos.

OnC such place . • was Press House in Wellington. “There are five rooms in this building that have blue asbestos, coating on the ceilings, which is now being removed,” said Dr Nicol.

The people doing this wdrk have air-line breathing apparatus. “The asbestos is wetted and the next day scraped off with a trowel or spade. The scrapings are gathered, sealed in plastic bags and later buried under supervision.” Asbestos was used widely in the 1950 s and 19605, but its use tapered off in the 19705, said Dr Nicol. Its main use is in asbestos cement, and in brake linings. It is also sprayed in buildings as a sound deadener, to prevent condensation and it also limits the spread of fire. “Some ceiling coatings now have 2 or 3 per cent of asbestos in them, compared with 50 per cent a ■couple of years ago. It is more common to use glass-fibre based materials now.” Dr Stoke said asbestos fibres in the skin could start a Ideal reaction from a callous to a wart. Inhalation of fibres may

lead to their, being deposited in the lung tissue around the alveolus and the formation of scar tissue (asbestosis), •_ '

He said'.it' took at least 10 to 15 .years after that happened before the symptoms, a cough, and shortness of breath, appeared. “Our present standard is based on the fact that after constant exposure to asbestos for 50 years, 40 hours a week, less than 1 per cent of those so exposed will develop symptoms of asbestosis,” he said.

The recently published report in the United Kingdom by the Advisory Committee on Asbestos, has resulted in this control limit being renewed.

Little is known about the incidence of lung cancer in asbestos workers who do riot smoke. But there is no evidence that it is more prevalent than in the general population. Dr Stoke said that if signs Of asbestosis appeared in smokers the risk of lung cancer was increased 20-fold. An extremely rare tumour, mesothelioma, may develop 40 years after an unprotected person is exposed to medium or heavy concentrations of blue asbestos for a few weeks.