NCPA - National Center for Policy Analysis

Cancer Risks From Sludge are Small

January 22, 2004

There is negligible harm in using sewage sludge as a farm fertilizer, concludes a five-year study by the Environmental Protection Agency. Environmental groups have called for the government to regulate the use of sewage sludge, claiming that the chemical dioxin, found in sludge, adversely affects health by increasing the risk of cancer. However, the EPA's study concluded that:

  • In a worst-case scenario, where a farm family applies sewage sludge to their crops for a lifetime and then consumes a substantial amount of their own crops, the family would develop only 0.003 new cases of cancer.
  • Regulatory controls over manufacturing processes have already reduced dioxin levels in the environment by 90 percent since 1988.

Moreover, since the farm family example is not representative of most consumers of food, the risk to the population in general is even less than the risk to a farm family.

Geoffrey Grubbs, the EPA's director of water science and technology programs, says the risk of getting cancer from dioxin as being, "small, substantially smaller than other chemicals we regulate."

Additionally, the EPA found no significant effects on wildlife from the use of sludge, and for now does not plan to regulate the practice.

Source: James M. Taylor, "EPA: No Harm in Using Sewage Sludge as Fertilizer." Environment and Climate News, December 2003; based upon, "EPA Makes Final Decision On Dioxin In Sewage Sludge Used In Land Applications," Environmental Protection Agency, October 17, 2003..


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