For someone wishing to pursue the known, documented health effects of various materials, a Material Safety Data Sheet (MSDS) is the best place to start. An MSDS can definitely provide a certain amount of information, but with sensitive people, personal tolerability testing is still very important. This is because sensitive people react to all kinds of things—many of which aren’t listed on an MSDS—and a sensitive person’s metabolism is unique to them. They can also react to low-level exposures that aren’t necessarily dangerous to healthy people. Of course, as researchers learn more about how pollutants subtly affect the body, they may determine that what we once thought was a safe level of exposure is, in fact, unsafe.
The Occupational Safety and Health Administration (OSHA) has issued right-to-know regulations for the workplace. Material Safety Data Sheets (MSDS) are a big part of those requirements. The regulations were written to insure that hazardous chemicals produced, imported, or used within the U.S. are evaluated, and that information is given to the affected employers and employees. An MSDS should be available to all employees for each hazardous chemical they come into contact with.
An MSDS is a printed form, on which a manufacturer provides an emergency phone number and information about the harmful ingredients in a product. Required by law, it contains basic information such as a product’s name, boiling point, flammability, etc. You can get an MSDS for virtually any material on the market. Some may be available through local supply centers but often you’ll need to contact a manufacturer to obtain one.
An MSDS also lists hazardous ingredients and negative health effects. However, an MSDS does not always list all potentially hazardous ingredients—some formulas are considered proprietary or trade secrets by their manufacturers. In such cases, specific health-related information will be given to a physician in the event of a medical emergency, but it’s not listed on the MSDS. An emergency phone number is included for this reason. Also, when the percentage of a hazardous ingredient is below a certain level, it may not be listed. For example, if a hazardous ingredient, other than a carcinogen, comprises less than 1% of a product, it need not be listed. Carcinogens need not be listed on an MSDS if they are present in quantities less than 0.1%. As a result of all this, it’s not unusual for an MSDS to be incomplete or misleading.
Exposure limits
When a hazardous ingredient is listed on an MSDS, the amount causing negative health effects may be listed as a TLV (Threshold Limit Value), PEL (Permissible Exposure Limit), or LD50 (the Lethal Dose that kills 50% of lab animals). TLVs can be described in different ways: based on exposures over an eight-hour workday, a fifteen-minute exposure, or an instantaneous exposure. The smaller the TLV, PEL, or LD50, the more hazardous the substance. For example, the TLV for grain alcohol is 1,000 ppm (parts per million), turpentine 100 ppm, and formaldehyde 1 ppm. Just because a product contains only a tiny percentage of a hazardous substance doesn’t mean it’s safe—always look at the TLV, PEL, or LD50, as well as the percentage.
Unfortunately, TLVs, PELs, and LD50s have not been established for many hazardous ingredients. When this is the case, an MSDS can give you a false sense of security, because you will have no idea how hazardous the product product really is.
Health effects
The health-effects section of an MSDS will list short-term (acute) or long-term (chronic) health effects, based on different routes of exposure (inhalation, ingestion, absorption through the skin, eye contact). All the information on an MSDS is meant to be applicable to healthy adult workers during an eight-hour day. More susceptible people, such as children, the elderly, the sick, or people exposed to a substance for twenty-four hours a day, can be affected much more readily or severely. Chemically sensitive individuals, many of whom react to extremely low levels of hazardous substances, are not addressed on an MSDS at all.
Physical properties
An MSDS will often list the vapor pressure, vapor density, percentage of volatiles, and evaporation rate of a substance. These physical properties can be used to gauge the outgassing rate, but they can be difficult to analyze.
Despite rather serious drawbacks, an MSDS can be a good starting point in researching the healthfulness of a product. While they definitely contain some valuable data, the information is often difficult to interpret. A good guide to use in deciphering an MSDS is the American Lung Association's How to Read a Material Safety Data Sheet.
