Petroleum, or what is known among the general public as benzene, contains monocyclic aromatic hydrocarbon compounds. Benzene may contain lead or be lead-free. There are few studies that have examined the toxic effects of inhaling benzene fumes on experimental animals. This study aimed to investigate the sub-acute toxicity of inhaling benzene vapor in experimental rats. The rats were exposed to benzene vapors for 1, 2, and 4 hours daily for 5 days per week. The experiment lasted for 3 weeks. Benzene vapor inhalation for 4 hours per day resulted in 13.3% mortality in the last week of the study. The study also showed the presence of behavioral changes in rats, as demonstrated by low values of the head poking test at all times of exposure to benzene. Inhaling benzene vapors resulted in a statistical decrease in the rat's red blood cell number, weight gain, the level of dopamine in the serum, the hemoglobin concentration, as well as the high-density lipoproteins cholesterol (HDL-C). On the other hand, benzene vapor inhalation resulted in a noticeable increase in the number of white blood cells, platelets, liver enzymes (AST & ALT), kidney function (urea, uric acid, & creatinine), and also lipid profile (total cholesterol, triglyceride & low-density lipoprotein cholesterol (LDL- C)) in the serum. The study also reported pathological changes in the kidneys of rats when exposed to benzene vapor. The study confirmed the benzene toxicity, which could adversely affect the nervous system, blood picture, liver and kidney functions, as well as the image of lipids in the blood.
