What is Diatomaceous Earth?
Diatomaceous earth (DE) is a naturally occurring, soft, powdery sedimentary rock formed from the fossilized remains of microscopic aquatic organisms called diatoms. The rock is easily crumbled into a fine powder, which consists primarily of amorphous silica. When viewed under a microscope, these particles appear like tiny, sharp, cylindrical honeycombs. This unique physical structure is what gives DE its abrasive and absorbent properties, making it effective for a wide range of uses, from pest control to food processing.
The Critical Difference: Food Grade vs. Filter Grade
Understanding the distinction between different grades of diatomaceous earth is the most important factor for ensuring safety. The two primary types are food grade and filter grade, and their processing and safety profiles are completely different.
Food Grade Diatomaceous Earth
Food grade DE is mined from freshwater sources and is processed to contain very low levels of crystalline silica (typically less than 1%). This form is considered non-toxic and is approved by regulatory bodies like the FDA for various applications. It is safe for human and animal use, though inhalation should always be avoided.
Filter Grade Diatomaceous Earth
In contrast, filter grade (or pool grade) DE is mined from saltwater sources and undergoes a heating process called calcination. This process transforms the amorphous silica into a high concentration of crystalline silica, which is very harmful if inhaled. Filter grade DE is toxic and should never be used for pest control, consumed, or applied around humans and pets.
Is Food Grade DE Safe for Consumption?
The consumption of food grade diatomaceous earth is a popular topic in the wellness community, with many anecdotal claims about its benefits. However, while the FDA recognizes it as GRAS as an anti-caking agent, there is very limited scientific evidence to support the broader health claims.
- Anecdotal Claims: Proponents suggest internal benefits such as detoxification by binding to toxins, improved digestive health, and stronger hair and nails due to its silica content.
- Scientific Evidence: Most of these claims are not supported by robust scientific research. One small study in 1998 showed it might help lower cholesterol, but lacked a control group and requires further research.
- Dosage: There is no officially recommended dosage for human consumption as a dietary supplement. It is always wise to consult a healthcare provider before starting any new supplement.
- Side Effects: Some users report mild flu-like symptoms or digestive discomfort, which are anecdotal and not scientifically proven.
The Primary Risk: Respiratory and Skin Irritation
The main safety concern with any form of DE, including food grade, is the risk of inhalation. Even the fine particles of amorphous silica can cause irritation to the nose, nasal passages, and lungs.
- Inhalation: Breathing in large quantities of the dust can lead to respiratory irritation, coughing, and shortness of breath. While the risk of serious lung disease is primarily associated with inhaling crystalline silica from industrial grades, it is still crucial to avoid inhaling food grade DE dust.
- Skin and Eye Irritation: The abrasive nature of DE can cause dryness and irritation to the skin with prolonged exposure. It can also cause eye irritation if it gets into the eyes.
Safe Handling and Application Guidelines
To minimize risks and use food grade DE effectively, follow these safety guidelines:
- Wear Protective Equipment: When applying DE, always wear a dust mask or respirator to prevent inhalation. Gloves and eye protection are also recommended, especially for prolonged contact.
- Use Proper Application Methods: For pest control, apply a very thin, barely visible layer of dust. Piling it up is ineffective and creates unnecessary dust. A bulb duster can provide a more targeted application with less airborne dust.
- Treating Indoors: Apply to cracks, crevices, behind appliances, and along baseboards where pests hide. Avoid treating large open areas where dust might be disturbed. When treating carpets, apply a light dusting, leave for a few hours, then vacuum thoroughly.
- Reapply After Moisture: DE loses its effectiveness when wet. Reapply after rain or heavy dew if using outdoors.
- Store Properly: Keep the product in an airtight container in a cool, dry place, away from children and pets.
Safety Around Pets
Food grade DE is generally safe for use around pets when used correctly. Many people use it for natural flea, tick, and worm control.
- For External Parasites: A light application can help with fleas on bedding or in kennels. Avoid applying directly to a pet’s coat or skin, as the dust can cause respiratory or skin irritation.
- For Internal Parasites: It can be mixed into pet food, but a veterinarian should be consulted first, as efficacy is debated and proper dosage is important.
- Minimize Exposure: Always apply DE in areas inaccessible to pets while they are present. Keep pets out of treated areas until cleanup is complete.
Comparison Table: Food Grade vs. Filter Grade Diatomaceous Earth
| Feature | Food Grade Diatomaceous Earth | Filter Grade (Pool) Diatomaceous Earth |
|---|---|---|
| Source | Freshwater deposits | Saltwater deposits |
| Processing | Dried and milled | Calcined (heat-treated) |
| Silica Type | Mostly Amorphous Silica | High Crystalline Silica |
| Inhalation Safety | Respiratory irritant; avoid inhalation | Toxic; can cause silicosis |
| Consumption Safety | Generally safe for consumption | Never for consumption |
| Pest Control | Yes, non-toxic insecticide | No, toxic |
| Filtration | Inefficient for fine filtering | Highly efficient for pool filters |
Conclusion
Food grade diatomaceous earth is a versatile, non-toxic, and natural product that is generally safe when handled with care. The key to its safe use lies in proper product selection, ensuring you are using a certified food-grade product with very low crystalline silica content. The main safety precautions involve minimizing inhalation of the fine dust particles, using protective equipment during application, and storing the product away from children and pets. By understanding the critical differences between food and filter grades and following recommended guidelines, you can safely utilize food grade DE for a variety of purposes.
For additional information on pesticide safety, consult the National Pesticide Information Center (NPIC).
