As You Sow

Toxic Waste in California Home and Farm Fertilizers

Thursday, November 18, 1999

As You Sow

Toxic Waste in California Home and Farm Fertilizers

View and Download the report here: As You Sow

State and private laboratory tests show that fertilizer manufacturers routinely add undisclosed amounts of toxic waste to farm and home fertilizers sold in California. These companies buy toxic waste from industrial facilities to obtain low-cost plant nutrients, such as zinc or iron. Unfortunately, such waste streams are often highly contaminated with persistent toxic chemicals, including heavy metals and dioxins. Many of these contaminants are known to cause cancer, reproductive and developmental toxicity or other serious health effects and, to varying degrees, are available to be absorbed from the soil by food crops. Sold as household products, they may also pose a risk to home gardeners and their families. In spite of these risks, the California Department of Food and Agriculture has now proposed to legalize the practice recycling toxic waste into fertilizers.

Tests find popular home fertilizer highly contaminated

In tests of a widely-used home fertilizer sold throughout California, every sample exceeded State of California criteria for classification as hazardous waste, according to an analysis conducted for the California Public Interest Research Group (CALPIRG) and the Environmental Working Group (EWG). State data analyzed by CALPIRG and EWG also show that more than one-sixth of the commercial fertilizers tested by the California Department of Food and Agriculture (CDFA) exceeded State of California hazardous waste criteria for heavy metals including lead and arsenic.

Testing 10 samples of Ironite brand fertilizer purchased from home and garden stores in Los Angeles, San Diego, San Francisco, Sacramento and Fresno, an accredited independent laboratory found lead at three to four times the concentration that would require the fertilizer itself to be disposed of as hazardous waste. All ten samples also exceeded the hazardous waste criteria for arsenic, some by more than two times the standard. Thirty percent of the Ironite samples equaled or exceeded the hazardous waste criteria for mercury, and another 50 percent were barely below the standard. An average Ironite sample contained seven heavy metals, with average levels of lead at 3.7 times the hazardous waste threshold, arsenic at 1.9 times the threshold and mercury at 95 percent of the threshold. (Table 1.)

Table 1. Average Ironite sample compared to State of California levels for toxic waste.

Heavy Metal Level
Lead 370%
Arsenic 190%
Mercury 95%
Selenium 45%
Cadmium 27%
Barium <1%
Chromium <1%
Silver Not Detected

Ironite is recommended by its manufacturer for use on vegetables, flowers, lawns, potted plants, shrubs and trees. It is made by the Ironite Products Co. of Scottsdale, Ariz., using as raw materials the tailings from an abandoned lead and zinc mine. Due to its high levels of lead and arsenic, Ironite can not be used in Canada. Last year, Washington State officials issued a warning to consumers that Ironite could be "dangerous" and that ingestion of less than half a teaspoon could be toxic to small children. Using too much Ironite for only two years, state officials said, could make a back yard as contaminated as a hazardous waste site. As a result of these findings, Ironite reduced the product's recommended application rate -- but not its toxicity -- to comply with Washington State regulations.

One in six commercial fertilizers tested more toxic than hazardous waste

Contamination of agricultural fertilizers may be even more widespread. State data analyzed by CALPIRG and EWG show that more than one-sixth of the commercial fertilizers tested by the California Department of Food and Agriculture (CDFA) exceeded State of California hazardous waste criteria for heavy metals including lead and arsenic. Between 1994 and 1998, CDFA tested more than 250 samples of commercial (mostly agricultural use) fertilizer products for lead, arsenic and cadmium. Thirteen percent of the cadmium-tainted samples exceeded hazardous waste criteria, as did seven percent of the lead-containing samples and two percent of the arsenic-containing samples.

Spreading these contaminants on farm soils is a particular concern because lead, cadmium, arsenic and other contaminants persist and even accumulate in soil for decades where they may be absorbed by food crops. CDFA's assessment of the health risk posed by toxic fertilizer says that eating food grown with contaminated fertilizer will be the greatest single source of exposure for commercial products. (Risks posed by home-use products were not evaluated). Combined with the potential for exposures of toxic fertilizers stored at home, it is evident that contaminated fertilizers are a threat to farmers and farm workers, residents of agricultural communities, consumers anywhere of California produce, and home gardeners and their families.

Proposed state regulations won't protect Californians from toxic fertilizers

In the face of this evidence that home and farm fertilizers may be contaminated at levels harmful to human health, the State of California is about to issue proposed regulations that would continue to allow lead, arsenic and other toxic wastes to be added to commercial fertilizers at up to four times the level allowed in Washington State and up to 85 times the amount allowed in some European countries. Because the contaminants in question are highly persistent, and are expected to remain and accumulate in soils for decades or even hundreds of years, the Department is gambling with the future health of our farms and gardens. Given that many fertilizer products on the market are relatively clean, this is an unnecessary risk.

The state's proposed regulations are flawed at every turn:

  • Toxic wastes in home fertilizers would not be regulated at all, even though they present an obvious potential exposure route for children and other vulnerable populations.
  • The proposed rule would deny Californians the right even to know what toxins, and in what amounts, are in the fertilizer products they purchase.
  • The rule would regulate only three of the many contaminants found in fertilizer.
  • The proposed rule is based on a risk analysis that was designed with input from the fertilizer industry but not from environmental or public interest organizations; that has been widely criticized; inadequately peer reviewed; and that misses important sources of risk. A member of the state Scientific Review Panel called the proposed risk analysis "severely deficient."


State and independent tests that found highly contaminated samples of Ironite, the fact that it is not approved for use in Canada, and the consumer health warnings issued last year by Washington State argue strongly that this product may pose unacceptable health risks to Californians. CALPIRG and EWG urge California retailers to voluntarily remove Ironite from their shelves, and the state to require future packages of the fertilizer to carry warnings both of its toxicity to children at low doses and the potential for soil contamination.

The larger issue is that California farms and gardens should not be dumping grounds for industrial toxic waste. CALPIRG and EWG also urge the California Department of Food and Agriculture to reconsider its "risk-based" approach to regulating fertilizer. Rather than gamble with high levels of persistent contaminants in fertilizers, CDFA should:

  • Set soil standards that ensure that cropland and home gardens are not degraded by fertilizer use. Allowable contaminant levels in fertilizers should be set a level that would not result in increased contamination of soils.
  • Prohibit the use of toxic waste in fertilizers unless the waste is first fully treated according to federal and state guidelines for hazardous waste treatment.
  • Guarantee Californians' right to know about toxics in the fertilizers they buy, with labeling requirements that fully disclose the kind and amount of all toxic waste in the product.

View and Download the report here: As You Sow

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