Any chemical, including diatomaceous earth, can be harmful if you come into contact with large enough amounts. Therefore, it is not without risk. Some diatomaceous earth products are not checked for pest control-related risks. These include 'food grade' products and others that are not labeled for pest control. While some people may choose to use these products to control pests, the risks and effectiveness are untested and unknown. At the same time, users may not realize that these products can be hazardous. Because of this, they may not take any precautions. This can lead to unfortunate situations.
Some diatomaceous earth products are evaluated. These products will say they kill, repel, or help get rid of a pest on the package. They will also have an EPA registration number. Pesticide regulators determine the toxicity of these products and inform users with signal words. They also assess whether proposed uses are likely to result in high enough exposures to cause harm. Those uses that are found to be too risky are not allowed on labels. If protective equipment, such as a dust mask, is needed, that is also listed on the label. Additionally, for certain pests like bed bugs, manufacturers must evaluate the effectiveness of their products in ideal situations. In this way, pesticide labels help users minimize risks while maximizing the potential benefits.
When up to 2% is added to food, diatomaceous earth is generally recognized as safe by the US Food & Drug Administration. However, pest control uses typically involve spreading a more concentrated product within a home. In this scenario, breathing in the dust may be of greater concern. Also, higher concentrations can mean higher risk if someone is exposed. Without the benefits of a pesticide label, many unknowns remain for the 'food grade' user. However, you can always take steps to lower your risks by minimizing exposure.
If you have questions about this, or any pesticide-related topic, please call NPIC at 800-858-7378 (8:00am - 12:00pm PST), or email us at firstname.lastname@example.org.