Classification of hazardous materials by oral, dermal, and inhalational toxicities

Currently, no toxicity classification system exists in any formal sense for dermal and inhalational toxicities (the main routes of exposure in occupational environments), and, different criteria are used by regulatory agencies in the classification of toxicity by these routes. Therefore, a comparison of the acute toxicity information available for 582 chemicals with exposure standards was made with a view to establishing such a toxicity classification system. By sorting data on the basis of oral toxicity values, and dividing these values into toxicity classes (such as slightly toxic, very toxic, supertoxic), a strong correlation was found to exist between oral and dermal toxicity values, and oral and inhalational toxicity values. Indeed, overlap across toxicity classes was very small, and in most cases, clear demarcations existed. A toxicity classification system is proposed from these data. This classification system is based on a comparison of actual toxicity data, and is a true reflection of the interrelationships between oral, dermal, and inhalational toxicities.