Cancer-causing volatile organic compounds

October 2019

Summary

Many tap water contaminants can move from water into air and can enter the body through the skin after a shower or bath. The federal government classifies such substances as volatile organic compounds, or VOCs. These pollutants originate in multiple sources, including gasoline, solvents, paints, cars, carpets and shower curtains.

Between 1987 and 1992, the federal government set legal limits for 21 different VOCs in tap water. No new or updated federal standards for VOCs have been set since then. The legal limits allow much greater VOC exposure than the amounts many public health agencies consider pose minimal harm to human health.

The full range of potential VOC contaminants in everyday environments may include hundreds of chemicals. Most worrisome are those that harm the developing fetus or increase the risk of cancer. This report highlights 12 carcinogenic VOCs EWG believes should be regulated as a group of tap water contaminants.

Carcinogenic VOCs in tap water

In 2011 the Environmental Protection Agency recommended establishing a single regulatory standard for a group of carcinogenic VOCs, but it has not yet proposed a new standard. Of the 12 VOCs listed in the table below, the EPA recommended including nine in a group of potentially carcinogenic VOCs. EWG believes three additional chemicals should be added to the list: 1,4-dioxane, styrene and 1,1,2-trichloroethane.

What are the health effects of exposure to VOCs?

VOCs can cause various types of cancer. For instance:

• Benzene increases the risk of leukemia and lymphoma.
• Carbon tetrachloride, a solvent, increases the risk of non-Hodgkin lymphoma.
• Tetrachloroethylene, or PERC, a dry-cleaning chemical, can cause bladder cancer.
• Trichloroethylene, or TCE, a solvent and dry-cleaning chemical, can cause liver, kidney and blood cancer.

Some VOCs are not known to cause cancer but can cause other serious health problems. For example, toluene, ethylbenzene and xylene are toxic to the liver, kidneys and nervous system. Toluene is reported to harm the hormone system.

How do VOCs get in water?

VOCs are used in a wide variety of industrial and commercial products and processes. Commercial and residential applications, as well as disposal at municipal and industrial landfills across the country, have contributed to VOC contamination of drinking water supplies.

A 2006 U.S. Geological Survey study of groundwater and drinking water wells found VOCs in 90 of 98 aquifers tested nationwide, with the most frequent detections in California, Florida, Nevada and the New England and mid-Atlantic states. Some groundwater samples were contaminated with more than one VOC.

Is there a safe level of VOCs in water?

For most individual VOCs, limits that pose the one-in-a-million cancer risk defined by the California public health goals or the EPA are adequate. But the levels of some VOCs, such as trichloroethylene, need to be more strict to protect children.

Even these benchmarks may fall short, because people are exposed to VOCs and other pollutants simultaneously. That’s why EWG urges federal and state health agencies to regulate carcinogenic VOCs as a group.

What can I do to reduce my exposure to VOCs in drinking water?

There are many sources of VOC exposure:

• Drinking tap water that comes from polluted sources that have not been properly treated to remove VOCs.
• Inhaling VOCs that got into indoor air from contaminated tap water.
• Bathing or showering in water that carries VOCs.
• Inhaling indoor and outdoor air with VOCs that emanate from consumer products, or from industrial and commercial facilities that use these chemicals.

For many tap water quality concerns, shoppers can use EWG’s Water Filter Buying Guide to find a product that will remove specific water contaminants. Here’s what to look for:

• Many VOCs, though not all, can be effectively removed or minimized with basic countertop activated carbon filters, an economical option for mitigating water quality problems.
• More expensive technologies, such as reverse osmosis, offer even better water purification. This type of filter can be installed at the tap or as a whole-house water treatment.
• Finally, certain VOCs, such as 1,4-dioxane, can be removed only at the water utility level, because they require specialized treatment not available for homes.

Following the advice of federal and state public health agencies, EWG recommends that people whose water comes from a private well test their water quality regularly. This is especially important for private well owners in areas where there may be underground fuel storage tanks, or those near gas stations, dry-cleaning facilities and landfills.