Diatomaceous earth vs. boric acid

By Dr. Killigan
Diatomaceous earth vs. boric acid

The two most common powders on the market that can be used as insecticides are diatomaceous earth and boric acid. Both can kill bugs, but one is poisonous. Both have warnings, but one is generally recognized as safe by the U.S. Food and Drug Administration, while the other is not approved by the FDA.

This post aims to equip you with the knowledge you need to decide upon the proper powder of action for your particular situation.

What is diatomaceous earth?

Diatomaceous earth (DE) is a naturally occurring, soft rock that is made from the fossilized remains of tiny, aquatic organisms called diatoms, whose hard cell walls are composed of transparent, opaline silica. Deposits of silica, which is the same component that makes up glass, can be found in Poland, the Czech Republic, Germany, Denmark, France and several states within the United States, including Colorado, Nevada and California. These deposits actually make up 26 percent of the earth’s crust by weight.

DE is formed by the accumulation of diatoms (a type of algae) at the earth’s surface. Diatoms, which are microscopic and have sharp, pointed surfaces, have been on earth for a very long time, having first appeared in fossil records dating back to the Cretaceous period, which was more than 66 million years ago. They are found almost anywhere moist, including the sediment of river beds, lake beds, streams and oceans.

There are two main types of diatomaceous earth: food grade and filter grade. Food-grade is low in crystalline silica, non-toxic and considered suitable for human consumption, whereas filter-grade is high in crystalline silica, toxic to humans and inedible, but has many industrial uses.

What are diatomaceous earth uses (and a few other interesting facts)?

  • Diatomaceous earth has been used in toothpastes, metal polishes, facial scrubs, potting soils, beverages and water filtration systems. It has also been used as an insecticide, to remove parasites in animals and to improve cholesterol levels (as a dietary supplement).
  • DE is very hard. It is only two points lower than diamonds on the hardness scale.
  • The largest diatoms are about the width of a strand of human hair.

Is diatomaceous earth safe? 

Food-grade diatomaceous earth is purified. The FDA acknowledges food-grade diatomaceous earth as “Generally Recognized As Safe” (GRAS). (Please note that the industrial or filter-grade type used in pool cleaning is not classified as GRAS.) In addition, the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) classifies food-grade DE as safe for household use. Lastly, the Environmental Working group (EWG) defines food-grade DE as "fair" for personal use.

Exposure to DE can occur if you breathe in the dust or get it on their skin or in their eyes, as it can irritate your nose and nasal passages (if breathed in), cause irritation and dryness (if on your skin) or irritate your eyes due to its abrasive nature (if in your eyes). Any dust, including silica, can be irritating to the eyes.

This irritation can occur when applying DE or entering a space where the powder has not yet settled. (Once settled, there is no threat to exposure.) To prevent this, you can wear a mask, long-sleeved shirt, and safety glasses. It’s important to note that after inhalation of amorphous diatomaceous earth, which is food-grade and purified, it is rapidly eliminated from lung tissue.

How is diatomaceous earth beneficial? 

Diatomaceous earth is beneficial in that it kills pests physically (not chemically), working both externally and internally. Externally, its razor sharp particles, like tiny shards of broken glass, lacerate and puncture the tough, waxy layers that coat the exoskeleton of insects and pierce the soft bodies of other pests. This causes a pest’s body fluids to leak out, which, in term, causes the said pest to die of dehydation due to its rapid loss of fluids. Internally, when a pest tries to groom DE off of its body, whose fine particles have clung to its legs and are stuck between its exoskeleton joints, this powder, as it’s highly absorbing, soaks up the fluids in its body, thus (also) causing dehydration and death.

Diatomaceous earth remains effective as long as it is kept dry and undisturbed. It can be used on fleas, bed bugs, cockroaches, ticks, spiders, silverfish, ants and many other pests. Use the Insect Buster as an effective, safe, hyper-targeted and less-mess application tool for use against pests.

What is boric acid?

Boric acid, more specifically orthoboric acid, is a boron-containing compound. (Its molecular structure is h3bo3, as it is composed of boron, oxygen and hydrogen.) It is typically viewed as colorless crystals or a white powder. In nature, its mineral form is called sassolite. A USDA report states that “Although found naturally in some volcanic springs, there is no known commercially available natural source. Technical grade boric acid is manufactured by the reaction of borate salts with a strong acid.” Boric acid is also known as hydrogen borate, orthoboric acid and boracic acid.

Boric acid occurs in the environment and can be found in soil, water and plants. It is naturally present in vegetables, many fruits (including apples and bananas) and grains and nuts (including almonds and peanuts) but goes largely undetected as it is odorless and essentially tasteless. It is mined from the ground in several parts of the world, including Nicaragua, Mozambique, Italy, Japan and California.

Because its ions do not completely dissolve in water, boric acid is considered a weak acid. This weak acid has many natural attributes that help it to appear in a plethora of products, including antiseptics, flame retardants, insecticides (examples being ant and roach killers), household cleaners and laundry detergents. There are medical specialties that use boric acid, including dentistry, dermatology, infectious disease, naturopathy, obstetrics and gynecology, oral medicine, otolaryngology and wound care.

Boric acid and its borate salts are inorganic compounds with registrations for us as active ingredients in insecticides, herbicides, algaecides and fungicides. Because it is cytotoxic (toxic to cells), it can either disrupt the growth of or cause damage to various types of living every day annoyances, including bugs, weeds, fungi, mold and algae.

What are a few interesting facts about boric acid?

  • Boric acid ophthalmic (for the eyes) can be used an eye wash to cleanse or irrigate the eyes, a practice that was popular among the Greeks and the Romans. It can provide soothing relief for eye irritation and help remove pollutants, such as smog or chlorine, from the eye.
  • Boric acid can be used as a wound spray. When mixed with distilled water, this antiseptic solution can aid in treating minor cuts and burns.
  • Boric acid helps build bone density. Some women may benefit from dietary boron in order to increase bone strength and prevent fractures, as boron (one of its components) is an element that has proven effective in dealing with bone density loss and arthritis.

Is boric acid safe? 

A report published by the University of Maryland states that boric acid is not available as an FDA-approved product. According to a USDA report, it is registered with the EPA, in accordance with Section 3 of FIFRA, as a pesticide product. This report also states that boric acid is hazardous under the Occupational Safety and Health Administration's Hazard Communication Standard based on animal chronic toxicity studies.

Boric acid is not poisonous in the very small amounts that occur in nature. However, according to the U.S. National Library of Medicine, poisoning can occur if a pet or human swallows powdered products containing this chemical and chronic poisoning can occur when pets and people are repeatedly exposed to boric acid. High concentrations can potentially lead to reproductive problems, endocrine disruption, possible kidney damage, increased liver enzymes, allergic reaction, abdominal pain, irritation, burning sensations, central nervous system (CNS) stimulation and/or depression, diarrhea, rashes and vomiting. These quantities, estimated from accidental poisonings, are in the range of 5-20 grams for adults, 3-6 grams for children and less-than 5 grams for infants.

In addition, boric acid is a caustic chemical, meaning that if it comes into contact with tissues, it can cause injury. These injuries include burning or corroding people's skin, eyes and mucus membranes (lining of the nose, mouth, throat and lungs).

Are boric acid and borax the same? 

Boric acid and borax are similar, but not the same, as they come from two different formulations of the same compound. Boric acid is the extracted, processed and refined form of borax, being manufactured industrially from sodium borate minerals. It is used in chemical products. Borax is a mineral that is taken straight from the ground. It is used in cleaning products. 

Boric acid is used as an insecticide, a herbicide and a fungicide. 

  • As an insecticide. Boric act as a stomach poison in ants, cockroaches, silverfish, earwigs, bed bugs and termites, destroying their metabolism. In addition, it is very abrasive and can weaken the exoskeletons of insects and dehydrate them, from the outside in. It is an effective insecticide because the ant (or the cockroach or some other creepy crawlie), having been poisoned by the acid, goes back to its nest and spreads the love, which has a butterfly effect to every insect it interacts with. 
  • As a herbicide. It can cause desiccation or interrupt photosynthesis in plants. It can also suppress algae in swimming pools and sewage systems. 
  • As a fungicide. It serves as a wood preservative and controls decay-producing fungi in lumber and timber products.

Borax is used as a cleaner, in cosmetics, as an ant killer and an herbicide:

  • As a cleaner. Borax is used in various household laundry and cleaning products, including the 20 Mule Team Borax laundry booster and some tooth bleaching formulas and mouthwashes.
  • As a cosmetic product. It is an ingredient in various lotions, skin creams, moisturizers, sunscreens, scrubs, shampoos, and acne care products, as it prevents or slows bacterial growth in these moisturising products. 
  • As an ant killer. Borax is toxic to ants. Because it is slow-acting, worker ants will carry the borax to their nests and poison the rest of the colony
  • As a herbicide. It can lend a hand in the yard through a DIY weed killer recipe that is inexpensive and less toxic than many commercial weed killers.

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1 comment
  • Wow. Very informative. Thank you Dr. Killigan! I knew that boric acid wasn’t fantastic, but it’s great to know what the FDA, FIFRA, etc. has to say about it. Too, I actually didn’t know that boric acid and borax were so similar.

    Julie on

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