What Is Diatomaceous Earth and What Is It Used For?

Diatomaceous earth is a sedimentary rock with a wide range of applications. Diatomaceous earth is used for pest control and it is used in several products.

Diatomaceous earth is a sedimentary rock with a wide range of applications. It’s naturally occurring and is found in deposits around the world. Alternate names include diatomite and kieselguhr, which is German for “earth” and “sediment”. 

These days about 55 percent of mined diatomaceous earth is used in different types of filtration. The remaining 45 percent is used as an absorbent, filler, and in other applications. Less than one percent is used in unique pharmaceutical and biomedical processes. 

Diatomaceous earth is composed of the skeletons of ancient single-celled organisms called diatoms. Each species of diatom has a unique skeleton. But, for the most part, these skeletons are made of silica. Most of the diatomaceous earth we harvest today comes from deposits created in the Miocene and Pliocene eras — between 24 million and 2 million years ago.

By weight, silica makes up 26 percent of the earth’s crust. It’s found in emeralds, sand, quartz, and glass. The silica that gets incorporated into these skeletons came from a number of sources, including: 

• Volcanic ash
• Rocks
• Silica-rich plants

Diatoms are tiny, single-celled organisms. They’re algae that thrive in various environments like lakes, streams, and oceans. They’ve been abundant around the globe for millions of years and still exist in large quantities today. 

Depending on the conditions, this alga blooms several times a year. Each bloom contains billions of diatoms. After the organisms die, they settle in large quantities at the bottoms of oceans, lakes, and streams. Over thousands of years, a distinct layer of sediment forms called diatomite. 

Pure diatomaceous earth is a pale, chalky substance. It’s commonly a greyish color when it’s first mined and is rarely black. It’s very soft and fine-grained. 

One of the reasons that diatomaceous earth is used in so many applications is that it’s very mild and unreactive. It’s almost entirely chemically inert. This means it doesn’t react with many other chemicals in liquid or gas form. It doesn’t transmit heat easily. 

This porous, low-density substance floats on top of water until it becomes saturated. Depending on the quality, it can absorb anywhere from one and a half to four times its weight in water. This absorption process can take time because diatomaceous earth doesn’t dissolve well in water.

Diatomaceous earth is also a very stable substance. It doesn’t get broken down by sunlight. Microbes don’t degrade it. It also never omits any vapors, dangerous or otherwise. 

Diatomaceous earth is found in certain areas where there were ancient bodies of water. The U.S. both produces and uses the most diatomaceous earth worldwide. In 2021 the U.S. alone mined 830,000 tons of diatomaceous earth. This was worth about 274 million dollars. 

Six companies work with 12 mining areas and nine processing facilities throughout the Western U.S. The primary states for production are: 

• California
• Nevada
• Oregon
• Washington

The diatomaceous earth is extracted from large, open pits. The leading U.S. sources were once ancient freshwater lakes throughout the west and shallow marine environments in southern California. Places with large ancient silica and phosphorus deposits are the most likely regions to have large quantities of diatomaceous earth. Research also shows that the blooms were largest in lakes that weren’t too acidic or basic. Instead, these algae do best in water with a pH similar to tap water. 

The U.S. also imports diatomaceous earth from other sources around the world. The most prominent countries the U.S. imports from are: 

• Canada
• Mexico
• Germany

The price varies greatly depending on the quality. Although the diatomaceous earth itself isn’t harmful to the environment, mining practices can be. This is something that companies should keep in mind when they’re considering using this substance in their production chains. 

For the most part, diatomaceous earth is very safe for humans to use. The U.S. Food and Drug Administration (FDA) has labeled it GRAS, which means "generally recognized as safe." The FDA has also stated that it’s safe for animals to consume. 

Studies show that most of the diatomaceous earth we consume isn’t absorbed into our bodies. Instead, it passes through our digestive systems and is emitted as a waste product. 

But there are different versions of diatomaceous earth, and some are safer than others. Crystalline diatomaceous earth, for example, is tiny and sharp. It can be dangerous to your lungs when inhaled in large quantities. This type of diatomaceous earth is associated with respiratory problems like silicosis and chronic bronchitis. Small quantities of this type are used in some commercial pesticides. 

All types can irritate your nose and nasal passages if inhaled. Large amounts can cause coughing and shortness of breath. 

If it gets on your skin, especially repeatedly, it can cause irritation and dryness. It can also irritate your eyes. 

It’s also important to remember that some products and organizations make many false claims about diatomaceous earth. There has been very little research on the positive human health benefits of diatomaceous earth, so you should be highly skeptical of any claims like this. Examples of false claims include: 

• As a cure for various health problems — like knee pain
• As a way to remove toxins from your body — this application is only safe for use in environmental applications
• As an internal dewormer in animals

The FDA tries to monitor fraudulent claims like these. But you need to make sure that you double-check any seemingly unbelievable claims about diatomaceous earth and human health. 

Diatomaceous earth is sometimes used as a filler or additive in some products humans consume, like toothpaste. 

The FDA has also approved it for use in packaging. It’s safe to use diatomaceous earth in paper products and packaging that comes into contact with food. In this case, it’s predominantly acting as filtration and isn’t consumed. 

Regarding animal products, diatomaceous earth is used in many different animal feeds. It helps prevent feeds from caking together and also works as an inert filler. Products for animals can contain a maximum of two percent of diatomaceous earth by weight. 

This product has been registered for use as a pesticide and insecticide since the 1960s. For example, some farmers use diatomaceous earth in dust baths for their chickens. In a nine to one ratio with sand, diatomaceous earth can help prevent pests like: 

• Fleas
• Ticks
• Spiders

Dust baths can be very effective when you incorporate them into a large-scale integrated pest management system for your livestock. 

Diatomaceous earth can also help eradicate bed bugs — a common and problematic household pest. There are over 150 registered pesticides that contain diatomaceous earth. These products are specifically registered by the Environmental Protection Agency (EPA). You should look for their label to ensure that an insecticide is safe for home use. Always read the instructions on your pesticides and insecticides carefully before you use them. Follow these instructions exactly as they’re written. 

It’s important to note that diatomaceous earth isn’t an effective insecticide because it’s toxic or poisonous to insects. Instead, it dries out these creatures and absorbs oils and fats from their exoskeletons. This means that it kills them with contact. The sharp edges of crystalline forms also create cuts and micro abrasions on the insects. 

Diatomaceous earth has a wide variety of industrial applications. The two main applications are as a filtration additive and as an inert filler. 

Examples of these industrial applications include use as: 

• An additive in particle boards — when combined with urea, it cuts down on the release of formaldehyde by 50 percent
• An absorbent in industrial spills — for example, it can remove bacteria, protozoa, and viruses in public water systems
• An additive in pet litter
• A component in various forms of insulation
• An abrasive in certain polishes — this is particularly the small, sharp varieties of diatomaceous earth
• An additive in cement — this is the second most common use for diatomaceous earth in the U.S.
• A filter in certain pharmaceutical applications
• A filter for human red blood cells in certain medical applications

Depending on how you use diatomaceous earth, there are many similar materials you can use as a substitute. 

For example, there are various bedbug and pest treatment options that don’t include diatomaceous earth. But it’s important to remember that diatomaceous earth is one of the safest options for this application. 

Other substances can also be great as fillers or for filtration in industrial uses. Similar chemicals include: 

• Perlite
• Silica sand
• Clay
• Ground limestone
• Ground mica
• Bentonite

The best option for your application will most likely come down to price and product effectiveness. For the most part, diatomaceous earth is cheap to mine. Transportation is one of the greatest costs, so it’s essential to consider the source of your diatomaceous earth. 

Different mines also produce varying qualities of the substance. Always use food-grade diatomaceous earth if your application comes in contact with anything that people or animals consume.