Handling of Common Chemicals that are Particularly Hazardous Many compounds found in older literature have been found in recent years to be more hazardous than once thought. When the research was preformed, these compounds were readily available and the chronic effects were not known. Therefore, if you use a procedure not recently published, you must check the MSDSs of the reagents to get the most recent information on hazardous health affects. For the compounds listed below, consider finding a substitute solvent or reactant to avoid possible risk. If you cannot find as substitute, then take special precaustions to avoid exposure.
Chronic poisoning can occur by inhalation of relatively small amounts over a long period of time.
The toxic action is primarily on the blood-forming organs. Benzene has been documented to cause leukenia. Benzene is readily absorbed through the skin. Toluene should be substituted whenever possible. OSHA permissible exposure limit is 1 ppm.