Benzene C 6 H 6

1. Benzene C6H6 Abigail Flores

2. What is Benzene? • A colorless, sweet smelling liquid or an aromatic hydrocarbon, (light yellow at room temperature) • The Department of health and Human Services as well as other agencies have deemed it as carcinogenic to humans • Most people can begin to smell it at 1.5-4.7 ppm in the air, in water at 2ppm • Highly flammable • Evaporates quickly • Its vapor is heavier than air, long term stability in the atmosphere • Can dissolve slightly in and float on water

3. Where it’s found and how it’s used • Formed from both natural processes and human activities • Natural sources: volcanoes, forest fires, crude oil, gasoline, and cigarette smoke • Used to make other chemicals needed to make plastics, resins, nylon and synthetic fibers • In some types of lubricants, rubbers, dyes, detergents, drugs, and pesticides • In the US, benzene ranks in the top 20 chemicals for production volume.

4. Other Uses and Medical Tests • Used in the production of styrene, some types of rubbers, lubricants, dyes, drugs, synthetic detergents, insecticides, fumigants, solvents, paint removers, and gasoline • It’s also a byproduct of the coking process during steel production • Benzene ranks # 6 on the CERCLA Hazardous Substance List. • Most tests for benzene are available at your doctor’s office and they can test your breath or blood • However, these tests must be done shortly after exposure and testing your breath isn’t helpful in detecting low levels of benzene • Your urine can be tested by checking for the metabolite phenol, but this also has to be done soon after exposure and is only helpful when you’ve been exposed to benzene in the air at levels of 10 ppm or more • Plus, it isn’t a reliable indicator of the amount of benzene you’ve been exposed to because phenol in urine also comes from other sources • Measurements of muconic acid or S phenylmercapturic acid in the urine are more sensitive and reliable indicators of benzene exposure

5. Exposure • Outdoor air contains low levels of benzene from tobacco smoke, gas stations, motor vehicle exhaust, and industrial emissions. • Indoor air generally contains higher levels of benzene. The benzene in indoor air comes from products that contain benzene such as glues, paints, furniture wax, and detergents. • The air around hazardous waste sites or gas stations can contain higher levels of benzene than in other areas. • Benzene leaks from underground storage tanks or from hazardous waste sites containing benzene can contaminate well water. • People working in industries that make or use benzene may be exposed to the highest levels of it.

6. Symptoms • Immediate signs after breathing • Drowsiness • Dizziness • Rapid or irregular heartbeat • Headaches • Tremors • Confusion • Unconsciousness • Death (at very high levels) • Eating foods or drinking beverages • Vomiting • Irritation of the stomach • Dizziness • Sleepiness • Convulsions • Rapid or irregular heartbeat • Death (at very high levels) • If a person vomits because of swallowing foods or beverages containing benzene, the vomit could be sucked into the lungs and cause breathing problems and coughing. • Direct exposure of the eyes, skin, or lungs to benzene can cause tissue injury and irritation. • Showing these signs and symptoms does not necessarily mean that a person has been exposed to benzene. • More than 300, 000 people a year are exposed to the chemical and kills over 10,000 a year in the U.S. alone

7. Ways to Control Benzene • Fuel evaporative controls were installed on all 1971 light-duty gasoline vehicles • Mobile sources account for about 85% of all benzene emissions • An absorption/regeneration system (controls evaporative emissions) is a canister of activated carbon that traps vapors such as benzene

8. Long-term Effects • Long-term exposure (1 year or more): can cause bone marrow not to produce enough red blood cells, which can lead to anemia. • It can also cause excessive bleeding and can affect the immune system, increasing the chance for infection. • Animal studies have shown low birth weights, delayed bone formation, and bone marrow damage when pregnant animals breathed benzene. • The Department of Health and Human Services (DHHS) has determined that benzene causes cancer in humans. Long-term exposure to high levels of benzene in the air can cause leukemia, cancer of the blood-forming organs.

9. Government Regulation • The U.S. Environmental Protection Agency regulates benzene in the air and water, as well as emissions by industry.  The EPA has passed laws to limit the use and release of benzene to keep levels as low as possible.  • Regulations set by the Occupational Safety & Health Administration limit workplace exposure to a maximum of 1 ppm, averaged over an 8­hour workday. • Safe Drinking Water Act of 1974: requires the EPA to determine safe levels of chemicals in drinking water.  Benzene's level was set to zero. • This level is the maximum contaminant level goal (MCLG) for benzene but the maximum contaminant level (MCL) is 5 ppb

10. Case Study: Ibigawa, Gifu, Japan • Ceramics and solvents such as benzene were being freeze-dried using liquid nitrogen in an electronic parts factory • Oxygen liquefied at a liquid nitrogen temperature of -196 °C and it reacted explosively with benzene in a freezing mixture. • No preventive measures were taken because of lack of knowledge of benzene accidents. • Ceramic powder was mixed with one ton of benzene, and was frozen with liquid nitrogen at -196 °C. Work for transferring the freezing mixture to another container using a scoop started. An explosion occurred at 14:15 on January 17th, 1991. • All facilities of the factory including a ball mill mixer, a transfer pump, and an agitation vessel were damaged.An adjacent factory was destroyed. A drier and a steel plate roof were destroyed. • Two people died and one was injured. • Countermeasures taken: • Flammable solvents should not be used in a cooling process using liquid nitrogen. • The surface of liquid nitrogen should be isolated from the air. • Ignition sources such as mechanical stimulus and static electricity should be removed.

11. Sources • http://www.bt.cdc.gov/agent/benzene/basics/facts.asp • http://www.cancer.org/Cancer/CancerCauses/OtherCarcinogens/IntheWorkplace/benzene • http://resources.lawinfo.com/en/Legal-FAQs/benzene-exposure/Federal/is-benzene-regulated-by-the-u-s-government.html • http://water.epa.gov/drink/contaminants/basicinformation/benzene.cfm#four • http://www.eco-usa.net/toxics/chemicals/benzene.shtml • http://www.benzene.org/benzene-uses.html • http://www.sozogaku.com/fkd/en/cfen/CC1200022.html