Heating liquids increases vapor pressure even more and thus increases airborne concentrations. The way chemicals are used can cause them to become airborne. Finally, a word about protection. All of these factors can be controlled through adequate containment. Good ventilation, especially the fume hood, provides the best containment system for chemicals used in the laboratory.
Solvents are the most common group of laboratory chemicals.
They can be subdivided into aliphatic and aromatic hydrocarbons, both chlorinated and nonchlorinated. Alcohols and ketones are also in this class. Eye or mucous membrane irritations also may occur. In general, aromatic compounds are more toxic than aliphatic ones, and chlorinated compounds are more toxic than their nonchlorinated counterparts. An increase in chlorine atoms on a molecule usually increases toxicity.