Diseases Caused by Benzene

1. Introduction and Definitions

Benzene is a colorless, flammable liquid with a sweet odor, widely used in various industrial processes. It is a well-known human carcinogen, primarily affecting the bone marrow and blood system. Chronic exposure to benzene can lead to serious health issues, including leukemia and other blood disorders. This article aims to provide comprehensive information on diseases caused by benzene, targeting occupational health nurses and doctors.

2. Agent Causes the Disease

Benzene exposure occurs primarily through inhalation of its vapors, though it can also be absorbed through the skin or ingested. Common sources of benzene exposure in occupational settings include:

  • Petroleum Industry: Benzene is a natural component of crude oil and gasoline.
  • Chemical Manufacturing: Used in the production of plastics, resins, synthetic fibers, rubber lubricants, dyes, detergents, drugs, and pesticides.
  • Painting and Coating: Present in solvents and thinners used in paints and coatings.
  • Printing Industry: Utilized in printing inks and adhesives.

3. Workers at Risk of This Disease

Several occupations and tasks put workers at higher risk of benzene exposure, including:

  • Petroleum Refinery Workers: Exposed during the refining process of crude oil.
  • Chemical Plant Workers: Handling benzene in the production of various chemicals.
  • Painters and Coaters: Using products containing benzene.
  • Rubber and Plastics Industry Workers: Exposed to benzene during the manufacturing processes.
  • Laboratory Technicians: Using benzene as a solvent in laboratory settings.
  • Gas Station Attendants: Exposed to benzene fumes from gasoline.

4. Symptoms

Symptoms of benzene-related diseases can vary depending on the level and duration of exposure:

  • Acute Exposure: Symptoms include dizziness, headache, drowsiness, confusion, tremors, and unconsciousness. High levels of exposure can lead to respiratory failure and death.
  • Chronic Exposure: Long-term exposure can cause bone marrow suppression, leading to blood disorders such as anemia, leukopenia, and thrombocytopenia. It can also result in leukemia, particularly acute myeloid leukemia (AML).

5. Diagnosis

Diagnosing diseases caused by benzene involves a combination of clinical evaluation, occupational exposure assessment, and specific tests:

  • Medical History and Physical Examination: Detailed assessment of the patient's work history and symptoms.
  • Blood Tests: Complete blood count (CBC) to check for abnormalities in blood cells. Bone marrow biopsy may be necessary to diagnose leukemia.
  • Biological Monitoring: Measuring benzene or its metabolites (e.g., phenol, t,t-muconic acid) in blood or urine to assess exposure.
  • Imaging Tests: X-rays or MRIs to detect abnormalities in bone marrow.

6. Treatment

Treatment for benzene-related diseases focuses on managing symptoms and preventing further exposure:

  • Remove from Exposure: Immediate removal from the source of benzene exposure is crucial.
  • Symptomatic Treatment: Providing medications and supportive care to manage blood disorders. This may include blood transfusions, antibiotics, and growth factors to stimulate blood cell production.
  • Chemotherapy: For patients diagnosed with leukemia, chemotherapy is the main treatment.
  • Bone Marrow Transplant: In severe cases of leukemia, a bone marrow transplant may be necessary.

7. Prevention

Preventing benzene-related diseases involves implementing strict control measures in the workplace:

  • Engineering Controls: Using local exhaust ventilation, enclosed processes, and proper maintenance of equipment to reduce airborne benzene.
  • Work Practices: Implementing safe work practices such as proper handling and disposal of benzene-containing materials, and avoiding eating, drinking, or smoking in areas where benzene is used.
  • Personal Protective Equipment (PPE): Providing and ensuring the use of appropriate respirators, protective clothing, and gloves.
  • Health Surveillance: Regular health screenings, including blood tests and biological monitoring, for workers exposed to benzene.
  • Education and Training: Informing workers about the hazards of benzene and safe work practices to minimize exposure.

By recognizing the hazards of benzene exposure and applying effective preventive strategies, occupational health professionals can substantially lower the occurrence of related illnesses and improve the overall health and safety of workers.

Workplace Exposure Limits:

  1. OSHA PEL (Occupational Safety and Health Administration):

    • 8-hour Time-Weighted Average (TWA): 1 part per million (ppm)
    • Short-Term Exposure Limit (STEL): 5 ppm
  2. NIOSH REL (National Institute for Occupational Safety and Health):

    • TWA: 100 ppm (435 mg/m³)
    • Short-Term (ST) Exposure Limit: 125 ppm (545 mg/m³)
    • NIOSH also considers benzene a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990]. Additionally, the NIOSH REL includes:
      • TWA: 0.1 ppm (0.435 mg/m³)
      • STEL: 1 ppm (4.35 mg/m³)