Routes of Chemical Entry

Hazardous chemicals may enter and affect the human body through: Inhalation, Ingestion, Injection, and Eye and Skin Absorption. See Appendix D for more information on specific chemical exposures.


Inhalation of aerosols of solid particles (dust, fume) or liquid droplets, or inhalation of gases or vapors is a rapid and highly efficient manner of absorbing hazardous materials. Inhalation of a chemical may cause bronchial irritation, dizziness, central nervous system depression, nausea, headache, coma, or death. Prolonged exposure to excessive concentrations of solvent vapors may cause liver or kidney damage. The consumption of alcoholic beverages can enhance these effects.

The degree of injury resulting from exposure to toxic vapors, mists, gases, and dusts depends on the toxicity of the material and its solubility in tissue fluids, as well as on its concentration and the duration of exposure. Chemical activity and the time of response after exposure are not necessarily a measure of the degree of toxicity. Several chemicals (e.g., mercury and its derivatives) and some of the common solvents (benzene) are cumulative poisons that can produce body damage through exposure to small concentrations over a long period of time.


Taking in hazardous materials by mouth is obviously an efficient method of introducing contamination into the body. Mouth pipetting, eating, drinking, smoking, vaping, and applying cosmetics is forbidden in labs to reduce the possibility of ingesting hazardous materials. Food and drink may not be stored or consumed in areas where hazardous chemicals, radioactive materials, or biohazardous materials are being used. Hands must be well washed after laboratory work to prevent hazardous materials being transferred to food, etc., outside the lab. Ingestion of a chemical may cause sever toxicological effects. Seek medical attention immediately.


Piercing the skin with contaminated needles or other sharp objects may introduce hazardous materials into the body. Extreme care must be taken when handling needles and cannulation. Avoid needle poke injuries and exposure by not recapping needles. Place all sharps like needles and razor blades into an appropriate sharps container immediately after use (hard plastic container labeled sharps). Needles or other sharp objects should NEVER go into the trash. Contaminated broken glass should be placed into a separate glass waste container than clean broken glass waste and labeled for broken glass and the contamination. Do not attempt to clean broken glass.

Eye and Skin Absorption

Eye contact: eyes are not only very sensitive to damage by hazardous materials, but they also absorb solid, liquid, and gaseous chemicals much faster than skin. If you do get chemicals in your eyes, immediately go to an eyewash station. Once the eyewash has been activated, use your fingers (make sure to take off gloves and that your hands are clean!) to hold your eyelids open and roll your eyeballs in the stream of water so the entire eye can be flushed. After flushing for at least 15 minutes, seek medical attention immediately and complete an Incident Report. The importance of flushing for at least 15 minutes cannot be overstated! If you usually wear contacts, it might be best to talk with your PI to obtain prescription safety glasses. A chemical exposure while wearing contacts can exacerbate injuries. If there is a potential of splashing while working, utilize safety goggles and not glasses, as chemicals can still run down into your eyes while wearing safety glasses.

Skin contact: many chemicals are absorbed through the skin at a significant rate. Although this effect is usually most pronounced with liquids, there are solid chemicals which are hazardous when they come in contact with the skin. Even certain toxic gases may be dangerously absorbed through the skin, but exposure to concentrations of gas able to do this should never be encountered in a research lab. Skin contact with chemicals may lead to defatting, drying, and skin irritation.

For small chemical splashes to the skin, remove any contaminated gloves, lab coats, etc., and wash the affected area with soap and water for at least 15 minutes. For large chemical splashes to the body, it is important to get to an emergency shower and start flushing for at least 15 minutes. Once under the shower, and after the shower has been activated, it is equally important to remove any contaminated clothing. Failure to remove contaminated clothing can result in the chemical being held against the skin and causing further chemical exposure and damage. After flushing for a minimum of 15 minutes, seek medical attention immediately and complete an Incident Report.

Chemical Hygene Plan - Table of Contents