N Engl J Med 1987;316:1044–9. 12. Benzene has a boiling point of 80.1 °C (176.2 °F) and a melting point of 5.5 °C (41.9 °F), and it is freely soluble in organic solvents, but only slightly soluble in water. Prophylactic antibiotics and blood transfusions should be avoided unless a significant deterioration of his condition becomes evident. Benzene oxide may also react with GSH forming phenylmercapturic acid, which is converted to benzene dihydrodiol by EH, with subsequent conversion to catechol. Initially, increased risks of leukemia, predominantly AML, were reported among workers with high levels of benzene exposure in the chemical, shoemaking, and oil-refining industries, whereas more recently studies have focused on workers with lower exposure. Workers employed in industries using or producing benzene have the greatest likelihood of exposure. On examination, you find a muscular man with somewhat pale and dry skin. Since the 1950s, benzene production from petroleum feedstocks has been very successful and accounts for ∼ 95% of all benzene obtained. Betel Leaf. Sulfonated benzene derivatives are useful detergents. In one case report, an oral dose of 10 milliliters (mL) was reported to produce staggering gait, vomiting, tachycardia, pneumonitis, somnolence, delirium, seizures, coma, and death. medications. In the United States, the Environmental Protection Agency (EPA) has enforced limits on concentrations of benzene in drinking water, with the ultimate aim being to abolish it altogether. This risk has been lowered by installing vapor recapture devices on delivery hoses, which, if used properly, significantly reduce exposure. Immediate removal of the patient from exposure and administration of oxygen and cardiopulmonary resuscitation measures are the first consideration. Benzene exposure affects the central nervous system (CNS) and hematopoietic system and may affect the immune system. Benzoic acid is chemicals compunds has many used for food preservative. State Art Rev Occup Med 1988;3:541–54. Chemical of current interest-benzene. Switch between the Original Pages, where you can read the report as it appeared in print, and Text Pages for the web version, where you can highlight and search the text. [88] Benzene causes chromosomal aberrations in the peripheral blood leukocytes and bone marrow explaining the higher incidence of leukemia and multiple myeloma caused by chronic exposure. He has lived in his home for the past 16 years. To provide a mechanism for the conversion process, Kekulé proposed that the valency of an atom is determined by the frequency with which it collided with its neighbors in a molecule. [20] Four years later, Mansfield began the first industrial-scale production of benzene, based on the coal-tar method. The use of benzene as a solvent has declined in the recent years following its classification as a hazardous compound and carcinogen (ATSDR, 2007a). Early symptoms of chronic benzene exposure are often nonspecific but show marked individual variability. Patients with benzene-induced aplastic anemia have been observed to progress to a preleukemic phase and develop acute myelogenous leukemia. At higher exposure levels, metabolic pathways appear to become saturated, and a large portion of an absorbed dose of benzene is excreted as a parent compound in exhaled air. Privacy Policy | Uses of benzene. Along with mutagenic effects, benzene is believed to alter cell-signaling pathways that control hematopoiesis in hematopoietic stem cells.32 Workplace exposure restrictions have reduced human exposure to high levels of benzene. As the carbon atoms in the benzene ring collided with each other, each carbon atom would collide twice with one neighbor during a given interval and then twice with its other neighbor during the next interval. It has bad smell like rotten fish and easy to explode. For commercial use, until World War II, most benzene was obtained as a by-product of coke production (or "coke-oven light oil") for the steel industry. Follow-up of the workers a year after exposure ceased suggested that the effects of benzene can persist or can evolve overtime. Working off-campus? Aspiration of the marrow space often produces no sample (dry tap) in patients with aplastic anemia; however, a dry tap is not diagnostic of aplastic anemia; therefore, a biopsy specimen should be obtained as well and examined for architecture and cellularity. Toluene is also processed into benzene.[58]. Laboratory evaluation of benzene-exposed persons should include the following: CBC with differential, hematocrit, hemoglobin, erythro cyte count, erythrocyte indices (MCV, MCH, MCHC), and platelet count. The affected batches were removed from sale. The National Primary Drinking Water Regulations promulgated by EPA in 1987 set a maximum contaminant level for benzene of 0.005 ppm (5 ppb). Benzene exposure is associated with myelodysplastic syndromes. Owing to its high volatility, a significant amount of benzene evaporates before being absorbed through the skin (ATSDR, 2007a). 11,960) for the fractional distillation of coal tar. [38] If the anecdote is the memory of a real event, circumstances mentioned in the story suggest that it must have happened early in 1862. Most of these metabolites have some value as biomarkers of human exposure, since they accumulate in the urine in proportion to the extent and duration of exposure, and they may still be present for some days after exposure has ceased. Around the turn of the 20th century, benzene was also used to decaffeinate coffee. Benzene is the simplest and most important member of the aromatic hydrocarbons. He said that he had discovered the ring shape of the benzene molecule after having a reverie or day-dream of a snake seizing its own tail (this is a common symbol in many ancient cultures known as the Ouroboros or Endless knot). Absorbed benzene is rapidly distributed throughout the body and tends to accumulate in fatty tissues. The molecular structure of naproxen is shown at right. The limit of the fusion process is the hydrogen-free allotrope of carbon, graphite. After a single exposure, urinary excretion of phenol and hydroquinone is highest within the first 24 hours and is essentially complete within 48 hours. For clinical inquiries, contact ATSDR, Division of Health Education, Office of the Director, at (404) 639–6204. Potential agents include MFO-inducing drugs (e.g., phenobarbital, alcohol); conditions include those causing rapid synthesis of bone marrow. Benzene has also been shown to produce neurotoxicity, but only at very high doses (ATSDR, 2007a). As benzene can cause cancer, NIOSH recommends that all workers wear special breathing equipment when they are likely to be exposed to benzene at levels exceeding the REL (10-hour) of 0.1 ppm. Toxicol Ind Health 1987;3(1):205–66. Although naturally present in gasoline, benzene has been used as a fuel additive in amounts that vary depending on the formulation requirements of the producer (NTP, 2005c).

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