Among solvent classes, which are generally considered the least toxic?

Aliphatic hydrocarbons are generally recognized as the least toxic among solvent classes due to their chemical structure and properties. These compounds typically consist of straight or branched chains of carbon atoms, which makes them less reactive and less likely to produce harmful byproducts.

Aliphatic hydrocarbons are often used in applications that require solvents with lower toxicity levels, such as in paints, coatings, and cleaning agents. Because of their lower likelihood of irritating the skin or respiratory system and their lower potential for causing long-term health issues, they are preferred for consumer products and situations where safety is a priority.

In contrast, aromatic hydrocarbons contain a ring structure and can be more toxic due to their potential to cause significant health effects, including carcinogenicity. Naphthenic hydrocarbons, although less toxic than aromatic hydrocarbons, still pose more health risks compared to aliphatic hydrocarbons. Petroleum solvents can vary widely in their toxicity depending on their specific composition, but many contain harmful components. Therefore, aliphatic hydrocarbons stand out as the safest choice among commonly used solvents.