What Is Naphtha?

The New Jersey Department of Health says naphtha can be reddish-brown when it comes from coal tar or colorless to pale yellow when it comes from petroleum, with a gasoline-like odor, and that it is used as a solvent and in making varnish, adhesives, coatings and many other chemicals. The NIOSH Pocket Guide classifies petroleum naphtha as a flammable liquid with a flash point of minus 40 to minus 86°F and explosive limits of 1.1% to 5.9%.

NIOSH lists symptoms of exposure to petroleum distillates, or naphtha, including irritation of the eyes, nose and throat, dizziness, drowsiness, headache, nausea, dry cracked skin and chemical pneumonitis from aspirating the liquid. It lists a recommended exposure limit of 350 mg/m3 as a time-weighted average with a 1,800 mg/m3 15-minute ceiling, and an OSHA permissible exposure limit of 500 ppm. A 2025 case report in Frontiers in Medicine says the primary causes of death from naphtha exposure include respiratory failure and severe central nervous system injury.

Benzene is part of the concern. The New Jersey Department of Health lists a cancer hazard for naphtha because it may contain benzene, a carcinogen, and notes that many scientists believe there is no safe level of exposure to a carcinogen. In a 1977 criteria document on refined petroleum solvents, NIOSH emphasized that benzene, an established leukemia-causing agent, is present in small amounts in many refined petroleum solvents, and recommended that every effort be made to keep benzene exposure as low as possible.