Boric Acid Facts

In this article, we will give you some useful facts about boric acid, the chemical formula is (H 3 BO), and answer questions like what is boric acid used for? and where does it come from?

Please read on to find out the facts about Boric acid.

What is Boric acid?

Boric acid (H 3 bo 3)can also be known as, boracic acid, hydrogen borate (BO 3) and orthoboric acid.

It is a weak acid and comes as a white powder that looks similar to baby powder, or it can be in the form of colourless solid white crystalline, the crystals are tasteless.

The chemical name is H 3 BO, and often written as B(OH)3 it contains the elements Boron, oxygen, and hydrogen. When occurring in this form it is a mineral and it is called Sassolite.

Boric acid is made from the same chemical compound as borax, even looking very similar.

Metaboric (HBO2) and Pyroboric (H 2 B 4 O7) and Boric oxide (B2O3)

The water in Boracic acid is lost when heated, it changes into different compounds, metaboric acid (HBO2) and then becomes pyroboric acid (H 2 B 4 O7) only when pyroboric acid (H 2 B 4 O7)  is heated over 300 centigrade.

Then it is Boric oxide (B2O3). The three are hydrates of Boric acid (B2O3). Orthoboric acid is soluble in water.

In summary

Boric acid is known as Orthoboric acid, Hydrogen orthobrate, and Boracic acid.

Elements of Boric acid are Hydrogen, Boron, and Oxygen.

The chemical formula of Boric acid, H 3 bo 3

Toxicity, Boric acid is toxic if consumed.


Borax is also called Sodium tetraborate (b 4 o 7) and comes in the form of white mineral powder crystals, its crystals give it a solid structure that is symmetrical due to its unique molecule pattern.

It has been used for many years now to clean things, Sodium tetraborate (b 4 0 7) is also useful for cleaning mould and mildew around the home.

It is a great solution, and most commonly used as a pesticide for getting rid of ants, cockroaches, mites and spiders, and for killing insects like wood-eating termites. Sodium tetraborate will not kill ticks or aphids.

You can make your own pesticide using Borax, just mix some of the borax powder with honey to make a paste and put it where you need it to work. The paste does a really good job of getting rid of the pests around the home.

Borax can be used to protect wood from fire, a solution is applied to the wood. You can buy borate rods to put into the wood, the chemical will then penetrate and treat the wood. It is also used to protect ancient ships and buildings.

It is also used in flame retardants. When applied to surfaces it will prevent smouldering, glowing and smoke. This is because Boric acid releases water, leading to char forming on the surface.

Borax is commonly used as a detergent booster for washing clothes, the white powder is able to remove tough stains from clothes.

It is not related to bleach and does not contain bleach, although people do add them together for greater cleaning powers.

Borax can be found in toothpaste, soaps and for teeth bleaching.

Like Boric acid, it is used during production to make ceramics, glass and pottery.

Borax is commonly used as a herbicide, it can be used in the garden to get rid of weeds, it is sprinkled around the weeds and left to do its job.

In the United States, the food and drug administration has banned it as a food additive.

Borax is used commercially, one of them being for gold mining.

Borates or Borax are a natural compound, it is water-soluble and is a salt-like acid.

Is Borax harmful?

Borax misuse and overexposure can cause serious side effects, the dust can cause irritation to the airways. It is a skin irritant, and if you touch it enough it will burn the skin.

Accidentally swallowing it can make you sick with stomach pain and diarrhoea.

Borax is thought of as being a green product because it is a natural mineral and it does not contain phosphates or chlorine.

You will find warnings on products containing Borax, with warnings of it being an eye irritant. These days it has been replaced by new ingredients in cleansers and cosmetics.


Boric acid is an acid of Boron, its salts are called borates. Boric acid and its sodium salts are pesticides found naturally around us.

Plants need Boron, the main compound of Boric acid to grow, too much of it, however, can be toxic and can affect the plant’s growth.

Recent data has found that the average intake of boron is 1.28 and 1.0 mg boron per day. In these small naturally occurring amounts of boron, it is not harmful.

Boron is made by treating borax with hydrochloric acid (na 2 b 4) and crystallising out the boric acid.

Boron dissolves in water. Boron can be removed from water with infiltration, using an anion exchanger.

Boron can be found in crop fertilisers and is used for soil lacking in Boron. Plants and crops grow better in soil with Boron in it.

It is applied to the surface of the soil and once wet it will dissolve its compounds into the soil. The roots of the plants or crops will take in the Boron which will help them grow taller.

When Boric acid is heated, the chemical produced is called Pyroboric acid (b 4 o 7).

One way of making Boric acid is by treating borax brine with a chelating agent, this will bind to the borates in the brine, which then becomes Boric acid.

Boric acid is used for the following:

Boric acid B (OH)3 is largely used with pesticides, it can be bought in many forms, as a powder, liquid or tablet, gel, paste, pellets and aerosols.

Boric acid can be found in a lot of products added during the manufacture of cleaning products, these might be used in homes, industrial factories, sewers, and hospitals.

Boric acid is also found in insecticides and is used in pest control, herbicides or found in fungicides, used to control fungus and mould.

Boric acid will kill ants, fleas, silverfish termites, cockroaches and is very effective at doing so.

Boric acid has been used to preserve foods because it is effective against yeasts, as early as the 1870s. Countries began to make it illegal to put in foods due to high levels of it being used, food was found to contain too much to be safe to consume.

Boric acid is also used to preserve wood and glass and also makes a good fire retardant.

Fire retardant

Boric acid is used as a fire retardant, as it has the ability to release water. Boric acid is used on many products like roofing membranes, electronics, appliance components, fabric, upholstery, mattresses and wall coverings to keep us safe.

Boric acid is better for use against insects indoors than Borax as it kills more types, and can stop insects from crossing boundaries.

Boric acid is effective at getting rid of fleas, applying plenty where flea eggs have been found and then leave it to work


It was discovered that Boric acid, which is a very weak acid, had properties that could act as an antiseptic.

Boric acid is also used in the manufacture of medicine and can be present in mild antiseptics, due to its antibacterial properties it is used to control bacteria.

Mixed as a very diluted solution Boric acid can be used as an effective eyewash.

Boric acid can also be used to treat athlete’s foot because it can kill bacteria.

Boric acid is a mild antiseptic and can be used to treat burns and cuts.

Silly putty

Boric acid is used in the manufacture of the material called silly putty! A general electric researcher trying to make synthetic rubber for use in world war 2, invented in the process another material that had different properties, silly putty was made by mixing silicone oil and Boric acid.

LCD Televisions

As well as other industrial products, Boric acid is used to make the glass in LCD televisions, its properties make the glass better, giving a clearer picture.


Boric acid is used in the production of glasses, including borosilicate (heat resistant glass). Around 10-20 % of glassmakers add boric oxide to the silica base, these compounds will lower the melting temperature of the glass.

Pyrex is a well-known make in kitchens, it contains Boric acid and Borax, it can be up to 5 times stronger than glass. Pyrex glass dishes can cope with temperatures up to 425 degrees Fahrenheit, making them great for use in cooking.

You can tell the difference between an ordinary glass dish and a pyrex one, as pyrex is stamped onto the dish.

Where does Boric acid come from?

Boric acid can be found in its natural form at the sites of volcanoes and hot springs and can occur in the dry salt lakes of Nevada and California at California’s Borax lake.

This is where it will appear in the form of the mineral sassolite.

Boric acid can occur naturally in plants, soil, and water, because it is a soluble solution it can travel through the soil. Boric acid can also be brought out by plants growing in the soil.

Boric acid is naturally present in most fruit, vegetables and grains, children and adults are probably eating Boric acid every day in their food, and water, and not knowing, as Boric acid crystals are tasteless and do not have an odour.


How does it kill pests?

The insects walk over the white powder and this is then absorbed into the body which damages the insect’s stomach. If insects eat the Boric acid it has the same effect on the stomach, poisoning the pests.

Boric acid can also damage the outside body of the pest.

Boric acid B(OH)3 and Borax (sodium tetraborate decahydrate) can also kill plants as it stops the growth of the plants, it is a sodium borate salt that will dry out plants.

Is Boric acid safe for humans?

Boric acid B(OH)3 is low in toxicity, but as borax ( a sodium borate salt), it can damage the eyes and irritate the skin.

If eaten, Boric acid commonly can make people feel sick, and actually be sick, and can cause diarrhoea and stomach pains, and weight loss. This can be followed by rashes, lack of energy, and weakness.

In high doses being consumed or long term consumption, can lead to coma, liver and kidney problems and eventually liver and kidney failure.

Therefore it is best to keep exposure and consumption of Boric acid as low as possible.

Exposure to Boric acid

Due to lack of data, it is not clear if infants are more sensitive to Boric acid than adults. Children play and explore, which could put them at greater risk of exposure to Boric acid. When using Boric acid it should be in use out of the reach of children so they do not come into contact with it.

Long term exposure is not a good idea.

If infants were to eat 5 grams of Boric acid it could cause death. Ingestion of 15-20 grams could cause death in adults.

According to the EPA, laboratory animals exposed to Boric acid did not have any signs of cancer.

Boric acid was once commonly used in the production of talcum and present in infants nappy powders, to ease rashes due to its antibacterial properties.

This compound was banned as it was decided that if it enters the body through an injury it is too toxic and could cause harm.

Is Boric acid safe for fish, birds and other animals?

Boric acid is commonly found naturally in soil, water and plants and it is not toxic to birds, and only slightly toxic to pond living animals such as fish and frogs.

Environmental protection agency or EPA

The EPA has stated that during tests Boric acid is practically non-toxic to bees.  During tests syrup fed to bees containing 50mg of Boric acid did not harm them in any way.

Large amounts containing over 100mg of Boric acid killed the bees.

And finally,

We hope you have found the information and facts related to Boric acid in this article helpful. Did you realise Boric acid was used for so many different things?

Should you have any questions please do not hesitate to contact us by dropping an email, we do our best to respond as quickly as possible. 

Ronald has 25 years of pest control experience under his belt. He scrutinizes each pest control method, product and process. 

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