Material Safety Datat Sheets (MSDS) Part II
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- Last Updated: Thursday, 19 June 2014 19:43
In this article we'll delve further into health hazards, how they are evaluated and classified. We'll provide a perspective on carcinogens and the most common ceramic material - Silica.
In Part III we'll discuss what a manufacturer is required to communicate on MSDS sheets, help define exposure limits and put them in perspective, and we'll point out the key sections of MSDS sheets that you'll refer to the most.
Physical, Environmental and Health Hazards
Three classes of hazards addressed on an MSDS sheet are Physical, Environmental and Health. An example of a physical risk is flammability and an example of an environmental risk would be something that could be harmful to aquatic life.
In the last newsletter we listed the 7 types of health hazards. Two health hazards that you will see associated with ceramic materials are "Carcinogenic" and "Irritant." Irritants normally carry an acute warning whereas carcinogens normally bear chronic warnings. The definitions of acute and chronic toxicity are:
- Acute Toxicity - an adverse reaction will occur within hours or days. An acute reaction might result in symptoms such as a skin rash, irritation to your eyes, or immediate sickness.
- Chronic Toxicity - an adverse reaction that will occur over time (months or years). A substance that causes cancer is chronically toxic.
Assessing a Health Hazard
Classification of a material as a health hazard involves assessment of information created by the manufacturer, independent research (universities, private labs) and government agencies. Human and animal data are two significant sources of information used to determine what type of health hazard should be associated with a material.
Carcinogens
In the case of carcinogens and/or suspected carcinogens, two organizations serve as the driving forces to coordinate additional studies and ultimately classify a material:
- The International Agency for Research on Cancer (IARC)
- The NTP - National Toxicology Program, Dept. Of Health & Human Services.
The complexity of interaction between and among US and international governmental agencies and private researchers is beyond the scope of this article. What is important to know is that carcinogenic materials are heavily researched and a material's classification can change as new information becomes available.
The current classification of materials evaluated by the IARC (as of July, 2009 - the number of substances in each category is in parenthesis) is as follows:
- Group 1: Carcinogenic to humans (108)
- Group 2A: Probably carcinogenic to humans (63)
- Group 2B: Possibly carcinogenic to humans (248)
- Group 3: Not classifiable as to carcinogenicity to humans (515)
- Group 4: Probably not carcinogenic to humans (1)
Silica
Silica is one of the most abundant materials in the earth's crust (sand is silica). There are several types of silica - most ceramic companies will list Quartz (CAS No. 14808-60-7) on their MSDS. Silica is a significant ingredient in ceramic glazes and clay.
Silica was first identified by the NTP to be "reasonably anticipated to be a human carcinogen" in 1991; its status was changed to "known to be a human carcinogen" in 2000.
The danger from Silica is dust; Silicosis and related lung diseases can be caused by over exposure to silica dust. Glaze, in the wet form which you use, poses NO inhalation danger. Silica, in respirable form, IS the hazard. This is why we go to great lengths to warn against creating dust AND spray applying (spray creates mist, which can be inhaled).
Hazard versus Risk
A Hazard produces an effect by virtue of an inherent property of a material. A Chronic hazard's effect can take years of over exposure to manifest itself.
The Risk of being affected is, in the case of all ceramic materials, controllable. Proper handling, dosage, exposure levels, using proper equipment, ventilation - all of these issues are addressed on a MSDS. While you can not remove the underlying hazard of a material, proper use, handling and storage will eliminate the risk.