Diatomaceous earth (DE) is a fine powder made up of the fossilised remains of small hard-shell algae, or diatoms. Because it is extremely porous, absorbent and abrasive, diatomaceous earth has a wide range of applications. It is commonly used as a filtration material, a natural insecticide, an anti-caking agent and an absorbent material for cleaning up spills. It also has dietary uses as dewormer in people and livestock. However, the same characteristics that make diatomaceous earth so useful also make it necessary to use with caution.
What Type to Use?
There are two types of diatomaceous earth. One is food-grade and is approved for use in gardens. It contains amorphous silica, which has relatively few sharp particles. This type is generally approved by the FDA and EPA and is the safest type of diatomaceous earth to use. The other type is used in swimming pool filters and contains crystalline silica, which is very sharp and abrasive. This type of diatomaceous earth is more dangerous and should be avoided.
Inhalation is the main concern when working with diatomaceous earth. Because it is composed of fine, sharp silica particles, inhaling it can cause dryness of the nose and mouth, sore throat and coughing. Use caution, especially if you have a respiratory illness or pre-existing cardiopulmonary condition. Wear a dust mask and work in a well-ventilated area. If you experience any respiratory symptoms, go to an area with fresh air. In extreme cases, inhalation could require artificial respiration, oxygen or medical care.
Skin and Eye Contact
Diatomaceous earth can also cause dryness and irritation of the skin and eyes. To be safe, avoid direct contact with skin. Wear gloves, long sleeves and goggles that seal around the edge. If you experience skin irritation, wash the area with soap and water for a minimum of 15 minutes. Change to clean clothes and shoes and wash the ones you were wearing. If you experience eye irritation, flush your eyes with cold water for at least 15 minutes and seek medical attention.
Risks of Ingesting
Consuming diatomaceous earth that is not food-grade, or consuming large amounts of it, may be harmful due its sharp edges and highly absorptive qualities. If you ingest it, drink several glasses of water. If you ingest a large amount, drink plenty of water and seek medical attention.
Diatomaceous earth is non-toxic and is probably safe for occasional use. However, long-term exposure in people who work with it has been linked to lung damage, silicosis and other pulmonary problems. Chronic exposure may also increase the risk of lung cancer.