General Information
Before using any chemical, even if it is something that you have worked with at home or in other situations, it is important to understand what the hazards may be and how to work with it safely.
In order to assess the hazards of a particular chemical, both the physical and health hazards of the chemical must be considered. Generally, more information is available about physical hazards than health hazards. An overview of basic toxicology and physical hazards follows.
Before using any chemical, the container label and SDS or other appropriate sources should be reviewed to determine what conditions of use may pose a hazard. Accidents with hazardous chemicals can happen quickly and may be quite severe. The key to prevention of these accidents is awareness.
Physical Hazards of Chemicals
The physical hazards of a chemical include its flammability and reactivity. Flammability is the tendency of a chemical to burn. The flashpoint, auto ignition temperature and flammable limits of the material may be found in the SDS, and are helpful in assessing the potential for a fire hazard under specified conditions.
Reactivity is the potential of the material to explode or react violently with air, water or other substances upon contact. The SDS furnishes this information in the Stability and Reactivity Data section.
Health Hazards of Chemicals
The health effects of hazardous chemicals are often less clear than the physical hazards. Data on the health effects of chemical exposure, especially from chronic exposure, are often incomplete. When discussing the health effects of chemicals, two terms are often used interchangeably - toxicity and hazard. However, the actual meanings of these words are quite different. Toxicity is the ability of a chemical substance to cause harm. Hazard is the likelihood that a material will cause harm under the conditions of use. Thus, with proper handling, even highly toxic chemicals can be used safely. Conversely, less toxic chemicals can be extremely hazardous if handled improperly.
The actual health risk of a chemical depends on the toxicity and the actual exposure. No matter how toxic the material may be, there is little risk involved unless it enters the body. An assessment of the chemical's toxicity and the possible routes of entry will help determine what protective measures should be taken.
Routes of Entry
Skin and Eye Contact
The simplest way for chemicals to enter the body is through direct contact with the skin or eyes. Skin contact with a chemical may result in a local reaction, such as a burn or rash, or absorption into the bloodstream. Absorption into the bloodstream may then allow the chemical to cause toxic effects on other parts of the body.
The absorption of a chemical through intact skin is influenced by the health of the skin and the properties of the chemical. Skin that is dry or cracked or has lacerations offers less resistance.
Wear gloves and other protective clothing to minimize skin exposure. See Personal Protective Equipment for more information. Symptoms of skin exposure include dry, whitened skin, redness and swelling, rashes or blisters, and itching. In the event of chemical contact on skin, rinse the affected area with water for at least 15 minutes, removing clothing while rinsing, if necessary. Seek medical attention if symptoms persist.
Chemical contact with eyes can be particularly dangerous, resulting in painful injury or blindness. Wearing safety goggles or a face shield can reduce the risk of eye contact. Eyes that have been in contact with chemicals should be rinsed immediately with water continuously, for at least 15 minutes. Contact lenses should be removed while rinsing—do not delay rinsing to remove the lenses—seconds count. Medical attention is necessary if symptoms persist.
Inhalation
The lungs are the most common route of entry for gases, vapors and particles. Such materials may harm tissue in the lungs or enter into the bloodstream.
Most chemicals have an odor that is perceptible at a certain concentration, referred to as the odor threshold. Olfactory fatigue may occur when exposed to high concentrations or after prolonged exposure to some substances. This may cause the odor to seem to diminish or disappear, while the danger of over-exposure may remain.
Symptoms of over-exposure may include headaches, increased mucus production, and eye, nose and throat irritation. Narcotic effects, including confusion, dizziness, drowsiness, or collapse, may result from exposure to some substances, including many common hydrocarbon solvents. In the event of exposure, close containers, open windows or otherwise increase ventilation, and move to fresh air. If symptoms persist, seek medical attention.
Chemicals that produce vapors should be used in a well ventilated area or with local exhaust ventilation. Occasionally, general ventilation may not be adequate and local exhaust ventilation may not be feasible, making it necessary to use a respirator. The use of a respirator is subject to prior review by EHS according to University policy, since their use is regulated by the federal Occupational Safety and Health Administration Respiratory Protection Standard. See Respirator Use for more information.
Ingestion
The gastrointestinal tract is another possible route of entry for toxic substances. Although it is unlikely that anyone would accidentally eat a chemical, exposure may occur as a result of eating or drinking contaminated food or beverages or touching the mouth with contaminated hands. The possibility of exposure by this route may be reduced by not eating, drinking, smoking, or storing food in the areas where chemicals are used or stored and by washing hands thoroughly after working with chemicals, even when gloves are worn.
In the event of accidental ingestion, immediately go to Employee Health at McCosh Health Center or contact the Poison Control Center, at 1-800-222-1222 for instructions. Do not induce vomiting unless directed to do so by a health care professional.
Injection
The final possible route of exposure to chemicals is by accidental injection. Injection may occur through mishaps with syringe needles, or through accidents with broken glassware or other sharp objects that have been contaminated with chemicals.
If accidental injection has occurred, wash the area with soap and water and seek medical attention, if necessary. Cautious use of any sharp object is always critical.