Composition and toxicity of petroleum products and their additives.

1. All petroleum based products are highly complex chemical mixtures. Although almost exclusively composed of hydrocarbons, the composition varies with the crude oil source. 2. Their toxicity for man is generally low but there are exceptions. Although irritancy and sensitization to specific ingredients may be demonstrated in animals, animal experiments are not a reliable indicator of sensitization potential in man. 3. Both product complexity and commercial considerations can make acceptable and meaningful compositional disclosures difficult. A nomenclature system exists which solves these problems. 4. Frame formulations would have some value to poisons centres dealing with petroleum product enquiries. 5. As legislation for the European Union is developed, the balance must be reached between disclosure of the (often confidential) precise chemical composition of products and a practical and useful composition for the guidance of users and medical personnel. This is a key issue with some petroleum products, mainly due to the additives used in them. 6. For several reasons, such as climatic conditions or logistics of supply, the various components, including additives, used in a branded product may vary because the final product composition is determined not by chemistry but by performance in service. 7. Lubricants may contain between 10 and 20% of additives; fuels contain additives only at parts per million levels. However, for both fuels and lubricants, toxicity from additives is rarely a matter of concern.