HAZMAT Response Discussion and Questions: Toxicology

Discussion

Skin Contact Hazards
The principal dangers of hazardous materials are toxicity, flammability, and reactivity. However, many hazardous materials have more than one dangerous characteristic. These materials can produce extremely dangerous and harmful effects on the unprotected or inadequately protected human body. The best action to take when dealing with an unknown chemical or with a chemical that has more than one dangerous characteristic is to assume the worst and to provide the largest safety margin possible.

The skin can absorb harmful toxins without any sensation to the skin itself. This means that fire fighters should not rely on pain or irritation as a warning sign of absorption. Some poisons are so concentrated that a few drops placed on the skin may result in death.

Skin absorption is enhanced by abrasions, cuts, heat, and moisture. This can create critical problems for fire fighters working at incidents that involve biological agents. Anyone with large open cuts, rashes, or abrasions should be prohibited from working in areas where they may be exposed to hazardous materials. Smaller cuts or abrasions should be covered with a nonporous dressing.

The rate of absorption can vary depending upon the body part that is exposed. For example, chemicals can be absorbed through the skin on the scalp much faster than through the forearm.

The high absorbency rate of the eyes make them one of the fastest means of exposure. This type of exposure may occur when a chemical is splashed directly into the eye, when the chemical is carried from a fire by toxic smoke particles, or when gases or vapors are absorbed through the eyes. Absorption of a chemical through the eyes also may be seen as an early warning signal for either PPE or SCBA failure.

Chemicals such as corrosives will immediately damage skin or body tissues upon contact. Acids have a strong affinity for moisture and can create significant skin and respiratory tract burns. However, acid injuries also create a clot-like barrier that blocks deep skin penetration. In contrast, alkaline materials dissolve the fats and lipids that make up skin tissue and change solid tissue into a soapy liquid. This process is similar to the way caustic chemical drain cleaners dissolve grease and other materials in sinks and drains. As a result, alkaline burns are often much deeper and more destructive than acid burns.