A Brief History of Absestos in New Zealand.

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There have been two plants producing asbestos cement products. The first was established in 1938 at Penrose in Auckland, by the Australian Company James Hardie Ltd. A second factory, operated by well known local company, Fletchers, was established in the Christchurch suburb of Riccarton in 1943.

Depending on the item being manufactured, they were made of a mixture of sand,  Portland cement, and usually between 5 and 15 percent of either Chrysotile, Amosite or Crocidolite. Asbestos was added because of its inherent properties (high tensile strength, fibrous nature and heat resistance) which provided reinforcing to the sheet material.

The Auckland plant produced asbestos cement products until 1987 although from 1983 asbestos had been phased out of sheet products and was only included in pipes. At peak production in the 1970’s the Penrose plant employed up to 600 employees at any one time.

The Christchurch plant, called Dunrock Industries, operated until 1974. Estimates of the numbers employed over the life of the factory vary between 900 and 2000 – and are confused by the fact that large numbers of casual workers were employed.

Types Of Asbestos Used at the Plants?

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The types of asbestos used varied, however the most common was the "white" variety Chrysotile, which was cheaper and more easily worked. Because the "blue" Crocidolite from South Africa was more expensive (presumed better) it tended to be used in only products requiring greater heat tolerance or strength (such as in pipes expected to be subject to higher pressures or temperatures). A lesser quality of Crocidolite from the Wittenoom mine in Western Australia was also used to some extent. Amosite, or "brown" asbestos was imported from Rhodesia (now Zimbabwe).

Insulation and Acoustic Products Containing Asbestos

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Another major use of asbestos in New Zealand was as the raw material for insulation and acoustic products. This saw the various types of asbestos mixed with a binder and spayed around boilers, pipes, ducts and other places where insulation against heat and noise was needed. From the 1950’s until the 1970’s thousands of tonnes of asbestos were applied in this way, most notably in the power stations built in the period, but also in railway workshops, shipyard buildings and maintenance and other large scale industrial applications. Most of the countires major industrial complexes where insualtion against heat used asbestos in some form.

Sprayed asbestos was also extensively used as a fire retardant for protecting structural steelwork. Usually the insulation was applied by contractors who mixed asbestos from the bags or sacks it had been imported in, before spraying the mixture on to chicken wire reinforcing.

Less Common Applications for Asbestos

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Some of the industrial applications were less obvious. For example, asbestos was commonly used in the brewing industry to filter beer from the 1920’s to the early 1970’s, and it was dropped into wine to act as finings and clarify the finished product. Another unusual use for blue asbestos was as a filtering component in gas masks. British Manufactured these were standard issue for troops and others from the First World War until after the Second World War. An inner core of asbestos was surrounded by woollen wadding, and the item was standard issue to all New Zealand Troops in danger of gas attack.

Where Did We get it From?

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Before the Second World War, asbestos was not imported in its raw state in sufficient quantity to appear in the import statistics. With the beginning of local manufacturing and an increase in post war construction, more than 2000 tonnes were being imported annually by the late 1940’s. This continued thoughout the 1950’s with peaks of up to 5000 tonnes in some years. Usage increased dramatically during the 1960’s and until well into the 1970’s with the 5000 tonnes being the minimum imported during that time and the average being closer to 8000 tonnes. Imported asbestos peaked in 1975 at 12,500 tonnes. As recently as 1983, 3000 tonnes was still being imported. Throughout the 40 years asbestos was imported, about two thirds was chrysotile from Canada, with the balance being made up of the various different types from Australia, South Africa or, to a lesser extent, the United States.

Asbestos was only ever mined in small quantities in New Zealand. Chrysotile was sourced from a single mine near Takaka in the South Island from the early 1950’s until early 1960’s. It was of low quality and had to be mixed with imported material. In the late 1960’s a sizable deposit was found near Dusky Sound, but for various reasons these were never exploited. Since 1984 the importation of Blue and Brown asbestos, in its raw state, has been banned.