Many solvents evaporate quickly, which results in harmful solvent vapors in the air, creating not only fire risks but also health risks for employees. Because most solvents send vapors into the air, inhalation is the most common route of exposure. Some solvents are more toxic than others, even with low toxicity solvents, an exposure to extremely high levels can cause sudden death. Some solvents have strong odors even at harmless levels while others have no odor at dangerous levels. “Once inhaled, solvent vapors can quickly move into the bloodstream.
Fortunately, in cases of inhalation of low concentrations of solvent vapors, symptoms often pass relatively quickly without causing permanent damage.
Workers who are exposed to solvent liquids and vapors for many years, however, can suffer more serious health problems.” (Source: ehsdailyadvisor.com)