Asbestos Brake Dust - Still a Health Hazard

[lolo pepe]

Asbestos Brake Dust Still A Hazard
by Larry Carley c2007

Though asbestos brake linings have been mostly phased out, contrary to popular misconception they have not disappeared altogether. According to one original equipment brake supplier, Ford was still using asbestos linings as recently as 1993 on the Crown Victoria to cure a brake noise problem. The same supplier also said asbestos linings are still used on some high end import vehicles such as Land Rover because of their good braking characteristics. What's more, asbestos linings are still readily available in the aftermarket.

Though asbestos linings were one used on virtually all vehicles, the arrival of front-wheel drive in the 1980s required semi-metallic front disc brake pads that could withstand higher operating temperatures. But the vehicle manufacturers continued to use asbestos linings on the rear brakes as well as the front brakes on most rear-wheel drive cars and trucks. Why? Because asbestos was and still is an excellent fiber for brake linings. It offers good strength, temperature and chemical resistance, and is cheap compared to other materials that are used for the same purpose. But the physical properties that make asbestos such a good fiber also make it a hazardous substance.

Asbestos fibers are long, thin and extremely small. Exposed fibers easily shred into thin needle like strands that can drift in the air and be inhaled. The size of the fibers are such that they are not easily filtered out by the mucus linings in the nose and lungs. Hence, the fibers lodge deep in the lungs where their sharp needle like presence becomes a source of constant irritation. To make matters worse, the human body cannot rid itself of these fibers because they are impervious to biochemical assault. So over time, exposure to asbestos dust may result in lung disease or cancer.

The asbestos hazard is associated primarily with those who work in the asbestos handling and processing industries. But once the asbestos fibers are encapsulated in other materials, they pose little danger to workers in brake, clutch or gasket manufacturing plants.

There is a danger, however, to brake technicians because of the dust that�s generated as brakes wear. As the linings wear, asbestos fibers are exposed and released as dust into the air. Some of the dust clings to brake parts and some of it is blown away. If a technician uses an air hose to blow out a brake drum or to blow dust off brake parts to "clean" them, the only thing he�ll succeed in doing is blowing billions of asbestos fibers into the shop environment. This will expose not only the technician himself to dangerous concentrations of asbestos fibers, but everybody else in the shop, too.

THE ASBESTOS BAN?

Back in early 1980s, the health conscious Scandinavians were the first to ban asbestos containing products, including brake linings, clutch linings and engine gaskets. This lead to the introduction of nonasbestos substitutes, and the rest is history.

In January 1986, our own Environmental Protection Agency proposed a ban on the production of nearly all products containing asbestos in this country. There would also be a ban on importing asbestos-containing products that would gradually phase down over a 10 year period, ending in a total ban by 1996.

For awhile, it seemed that asbestos was headed for extinction. Friction material and gasket suppliers worked hard to develop nonasbestos substitutes and gradually made the transition to these new materials. Nobody wanted the liability associated with asbestos. But the EPA proposed ban was eventually overturned in the courts. One reason was that the ban would have put a lot of brake rebuilders as well as others out of business.

So to make a long story short, asbestos is still with us. Since there is no way to know if a vehicle has asbestos brake linings or not, it is wise to treat every vehicle as though it might have asbestos linings. And even if a vehicle does not have asbestos linings, there are still concerns that other fibers used in NAO linings may pose the same long term health risks as asbestos!

That is why OSHA recommends using some type of wet cleaning (aerosol or a brake washer) or enclosed high efficiency vacuuming to keep brake dust to an absolute minimum. Wetting down the fibers with a liquid prior to wiping or washing them off prevents them from becoming airborne. The maximum permissible exposure limit (PEL) is now only 0.1 fibers per cubic centimeter of shop air over an 8-hour period.

http://www.aa1car.com/library/trtu796.htm


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the above article was published in the U.S.

since wala naman atang standards ang Pinas tungkol sa asbestos abatement, be careful na lang when working around brake systems employing unknown materials. baka magkaroon tayo ng "asbestosis" which is a chronic lung inflammation resulting from prolonged inhalation of asbestos particles. asbestosis is also known to cause lung cancer.

naalala ko tuloy ang metro manila streets with thousands of PUVs still employing the old brake drum systems...and when the wind blows, the air will be filled with this kind of dust...

[OTEP]

A very informative read, thanks lolo_pepe.

[lolo pepe]

you're welcome, doc.