Environmental factors can also increase an individual’s cancer risk. These include:

• Sunlight and ultraviolet (UV) light exposure. The sun provides warmth and light. However, it also produces UV radiation that can damage an individual’s eyes and skin – even on days that are overcast or cloudy. The two main types of UV rays are UVA and UVB rays. Both of these contribute to skin cancer, the most common type of cancer.
  
  To avoid becoming one of over a million individuals diagnosed with skin cancer in the United States each year, individuals should:
  
• • Limit direct exposure to the midday sun when the rays are the strongest
    
    
  • Wear clothing that protects as much of the body as possible
    
    
  • Wear a hat with a two- to three-inch brim to protect the head and neck
    
    
  • Use sunscreen with a Sun Protection Factor (SPF) of 15 or greater on all exposed skin, including the lips
    
    
  • Wear sunglasses that block 99 percent or more of harmful UV rays
    
    
  • Avoid indoor tanning booths and beds
    
    
  • Have the skin examined regularly by a dermatologist
    
    
• Chemical exposure. Exposure to certain chemicals can also increase a person’s risk of developing cancer. One such chemical is benzene, a colorless, flammable liquid that has a sweet odor. Environmental sources of this volatile chemical include:
  
• • Gasoline
  • Automobile exhaust fumes
  • Cigarette smoke (including secondhand smoke)
  • Coke oven emissions
  • Waste water from some industries
  • Household products (e.g., some cleaning products, detergents and glues)

Workers in certain industries are also exposed to benzene, and small amounts of the chemical are found in drinking water. The Environmental Protection Agency (EPA) limits for benzene in the public water supply is 5 parts per billion.

Limiting exposure to benzene and other carcinogenic chemicals may reduce the risk of cancer. Therefore, people should exercise preventative measures such as avoiding secondhand smoke and closing car windows when driving in areas of heavy vehicular traffic (which have increased concentrations of benzene).

Sometimes the public becomes concerned about so-called environmental cancer risks that have not been proven, or situations in which exposures to known carcinogens are at levels so low they are considered negligible. According to the American Cancer Society (ACS), there is no evidence to support that cancer can be prevented by avoiding exposure to the following sources: 

• Pesticides
• Non-ionizing radiation
• Toxic wastes
• Nuclear power plants
• Power lines
• Cellular phone towers