Purpose- The purpose of this tutorial is to provide information about asbestos, the potential health effects associated with exposure, and safety procedures that should be followed to reduce exposure and protect the health of employees.
Types of Asbestos- Asbestos can be defined as friable or non-friable.
Friable means that the material can be crumbled with hand pressure and is therefore likely to emit fibres. The fibrous or fluffy sprayed-on materials used for fireproofing, insulation, or sound proofing are considered to be friable and they readily release airborne fibres if disturbed.
Materials such as vinyl-asbestos floor tile or roofing felts are considered non-friable and generally do not emit airborne fibres unless subjected to sanding or sawing operations. Asbestos cement pipe or sheet can emit airborne fibres if the materials are cut, abraded or sawed, or if they are broken during demolition operations.
Asbestos related Terms
Asbestos containing material (ACM) means any material or thing that, as part of its design, contains asbestos.
Airborne asbestos means any fibres of asbestos small enough to be made airborne. For the purposes of monitoring airborne asbestos fibres, only respirable fibres are counted.
Asbestos means the asbestiform varieties of mineral silicates belonging to the serpentine or amphibole groups of rock forming minerals, including actinolite asbestos, grunerite (or amosite) asbestos (brown), anthophyllite asbestos, chrysotile asbestos (white), crocidolite asbestos (blue) and tremolite asbestos or a mixture of any of these.
Asbestos-contaminated dust or debris (ACD) means dust or debris that has settled within a workplace and is (or is assumed to be) contaminated with asbestos.
Exposure standard for asbestos is a respirable fibre level of 0.1 fibres/ml of air measured in a person’s breathing zone and expressed as a time weighted average fibre concentration calculated over an eight-hour working day and measured over a minimum period of four hours in accordance with:
• the Membrane Filter Method
• a method determined by the relevant regulator.
Friable asbestos means material that is in a powder form or that can be crumbled, pulverised or reduced to a powder by hand pressure when dry, and contains asbestos.
Respirable asbestos means an asbestos fibre that:
• is less than 3 micron metres (µm) wide
• more than 5 micron metres (µm) long
Non-friable asbestos means material containing asbestos that is not friable asbestos, including material containing asbestos fibres reinforced with a bonding compound.
Characteristics of Asbestos
Asbestos has several characteristics that make it desirable for many commercial uses. The fibers are extremely strong, flexible, and very resistant to heat, chemicals, and corrosion. Asbestos is also an excellent insulator, and the fibers can be spun, woven, bonded into other materials, or pressed to form paper products. For these reasons and because it is relatively inexpensive, asbestos has been widely used for many years and now is found in over three thousand different commercial products.
Exposure to asbestos fibers can cause serious health risks. The major risks from asbestos come from inhaling the fibers. Asbestos is composed of long silky fibers that contain hundreds of thousands of smaller fibers. These fibers can be subdivided further into microscopic filaments that will float in the air for several hours. Asbestos fibers can easily penetrate body tissues and cause disabling and fatal diseases after prolonged exposure.
Identification of Asbestos
There are many substances that workers contact that may contain asbestos and have the potential to release fibers. Only rarely can asbestos in a product be determined from labeling or by consulting the manufacture. The presence of asbestos cannot be confirmed visually. The only way to positively identify asbestos is through laboratory analysis of samples. If the presence of asbestos is suspected always assume that it is an asbestos containing material and have it analyzed.
Friable Asbestos
The potential for a product containing asbestos to release fibers depends on its degree of friability.
The white fibrous or fluffy spray-applied asbestos material found in many buildings for fireproofing, insulating, sound proofing, or decorative purposes are friable. Friable asbestos containing materials ACM is found primarily in building areas not generally accessible to the public, such as boiler and machinery rooms.
Health Hazards
The most dangerous exposure to asbestos is from inhaling airborne fibres. The body's defenses can trap and expel many of the particles. However, as the level of asbestos fibres increase many fibres bypass these defenses and become embedded in the lungs. The fibres are not broken down by the body and can remain in body tissue indefinitely.
The increase in the use of asbestos resulted in a dramatic rise in asbestos related diseases among workers. Exposure to asbestos can cause disabling respiratory diseases and several types of cancer. The main routes of exposure are inhalation and ingestion. The majority of people who died from asbestos exposure were exposed to very high concentrations of asbestos fibers at work and had little or no protection. These employees worked with asbestos regularly and for long periods of time. Examples include workers who held jobs in industries such as shipbuilding, mining, milling, and fabricating. Many of these workers were also smokers.
The most dangerous exposure to asbestos is from inhaling airborne fibers. The body's defenses can trap and expel many of the particles. However, as the level of asbestos fibers increase many fibers bypass these defenses and become embedded in the lungs. The fibers are not broken down by the body and can remain in body tissue indefinitely.
Inhalation of asbestos fibres can lead to the following diseases:
lung cancer – this is a malignant tumour of the bronchi of the lung. It usually develops after an interval from initial exposure to asbestos of 20 or more years after substantial exposure to asbestos;
mesothelioma – is a cancer of the pleura (lining) of the lungs or of the peritoneum (lining) of the abdomen. Fibre type, age at exposure and dose are all risk factors. Compared to asbestosis and lung cancer this disease occurs at lower doses.
asbestosis - a chronic fibrosis of the lungs which makes breathing difficult. The interval from initial exposure to the development of asbestosis is usually 15-30 years.
General Safety Procedures
Everyone has probably been exposed to asbestos because it is so widely used. However, the health risks associated with asbestos are directly related to the amount and frequency of exposure.
Decreasing exposure to asbestos will decrease the health risks associated with it. This can be done by following safe work practices and taking proper precautions.
The health risks associated with exposure to asbestos occur when it is disturbed and releases fibers into the air. To reduce exposure, it is important to know where asbestos is located and to minimize activities that will release fibers into the air. The potential for a particular form of asbestos to release fibers will depend on several factors including the degree of friability, wear, age, and location.
Exposure to asbestos fibers can be hazardous. The following general precautions will reduce exposure and lower the risk of asbestos related health problems:
1. Drilling, sawing, or using nails on asbestos materials can release asbestos fibers and should be avoided.
2. Floor tiles, ceiling tiles or adhesives that contain asbestos should never be sanded.
3. Use care not to damage asbestos when moving furniture, ladders, or any other object.
4. Know where asbestos is located in your work area. Use common sense when working around products that contain asbestos. Avoid touching or disturbing asbestos materials on walls, ceilings, pipes, ducts, or boilers.
5. All asbestos containing materials should be checked periodically for damage or deterioration. Report any damage, change in condition, or loose asbestos containing material to a supervisor.
6. Asbestos should always be handled wet to help prevent fibers from being released. If asbestos is soaked with water or a mixture of water and liquid detergent before it is handled, the fibers are too heavy to remain suspended in the air.
7. Dusting, sweeping, or vacuuming dry asbestos with a standard vacuum cleaner will put the fibers back into the air. A vacuum cleaner with a special high efficiency filter (HEPA) must be used to vacuum asbestos dust.
8. If a HEPA vacuum is not used cleanups must be done with a wet cloth or mop. The only exception to this would be if the moisture presents an additional hazard such as around electricity.
What is Asbestos?
How to Avoid Asbestos Exposure
In order to avoid being exposed to asbestos, you must be aware of the locations it is likely to be found. If you do not know whether something is asbestos or not, assume that it is until it is verified otherwise. Remember that you cannot tell if floor or ceiling tiles contain asbestos just by looking at them.
The OSU Environmental Health and Safety Department has a laboratory and a licensed asbestos abatement crew that can take samples from materials in order to determine whether or not they contain asbestos. If you need to have materials analyzed or tested for asbestos, please contact EHS at X47241. Never try to take a sample yourself unless you are licensed to do so.
If you have reason to suspect that something is asbestos, either because it is labeled as such, or because it something that is likely to contain asbestos (9" floor tile, for example), DO NOT DISTURB IT.
Never...
• Drill
• Hammer
• Cut
• Saw
• Break
• Damage
• Move
• Disturb
...any asbestos-containing materials or suspected materials.