To demonstrate and ensure the general safety of fertilizer products, the fertilizer industry, spearheaded by trade associations such as The Fertilizer Institute (TFI), spent several years conducting extensive product safety tests. These tests used protocols consistent with the Environmental Protection Agency’s (EPA) High Production Volume (HPV) Challenge. Along with extensive data already available on most fertilizer products, the industry used this information to develop reports on the human and ecological health hazards associated with the 25 fertilizer products most often used and produced in agriculture. The industry’s reports also included exposure information to put the hazard statistics into context. Data in the reports includes physical and chemical properties, environmental fate, mammalian and ecological toxicity.
The data demonstrated that all fertilizer products tested pose little risk to fertilizer manufacturer employees, end users, communities and the environment when used properly. These testing results were then compared against data generated by the EPA, the World Health Organization and others. Ultimately, the International Organization for Economic Cooperation and Development (OECD) and the EPA’s HPV Challenge accepted these results.
Many inorganic fertilizers – most prominently phosphate and potash – are made with materials obtained by mining. Because metals and other natural elements are naturally occurring, small amounts may be collected along with the fertilizer material in the mining process. Other types of fertilizers carry the possibility of contamination. Metals may be present in biosolid-based fertilizers (treated sewage sludge marketed as fertilizer by municipalities looking to offset waste management costs) and cement kiln dust packaged and sold as agricultural lime (a soil amendment used to increase the pH of acidic soil). In small doses, many of these trace elements are essential nutrients, but larger amounts may be hazardous.
The fertilizer industry, along with state and national regulatory agencies, has conducted extensive product testing and risk assessments to ensure that these elements do not pose a risk to people who apply or otherwise come into contact with fertilizers or the crops grown with them. Study results are consistent: fertilizer products not only meet national standards for metals content, but they also meet California’s more restrictive standard. Even when applied at eight times the recommended rate, uptake of undesired elements by crops was not enough to pose a health risk.