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Yes, some at-home COVID tests contain a toxic chemical, but they’re safe when used correctly

The liquid in some rapid at-home COVID-19 tests contains a small amount of the toxic chemical sodium azide, but they are safe when used properly.

Starting next week, every home in the United States will be able to order four more free at-home COVID-19 tests from the federal government. Since the start of the coronavirus pandemic, public health officials have said testing is one of the first lines of defense against limiting the spread of COVID-19. 

Rapid COVID-19 tests allow people to take their own sample in the comfort of their home and get a positive or negative result within 15 minutes. But now, claims are surfacing on social media suggesting that the at-home tests contain a potentially lethal ingredient. In fact, in the past week, several poison control centers around the country have issued warnings about the ingredient.


Do some at-home COVID-19 tests contain a toxic chemical?



This is true.

Yes, some at-home COVID-19 tests contain a small amount of the toxic chemical sodium azide, but poison control centers say the tests are safe when used correctly.


Most at-home COVID-19 test kits contain a nasal swab, a tube called an extraction vial and cap used to generate the test result, and a testing card. While procedures may vary between brands, the National Capital Poison Center explains on its website that the testing process usually involves placing the nasal swab tip into both nostrils. This is followed by mixing the test swab with the contents of the extraction vial, which generates the chemical reaction that provides a positive or negative test result.

Sodium azide, a potentially lethal chemical, is used as a preservative agent in the extraction vial of many rapid COVID-19 tests kits. The Centers for Disease Control and Prevention (CDC) defines sodium azide as a “rapidly acting, potentially deadly chemical that exists as an odorless white solid.” Sodium azide is best known as the chemical found in airbags, the CDC says. It is also used as a chemical preservative in hospitals and laboratories, as a pest control agent, and it can be found in detonators and other explosives.

COVID-19 test kit brands, such as the BinaxNow, BD Veritor, Flowflex, and Celltrion DiaTrust, all contain sodium azide, according to the National Capital Poison Center and the U.S. Food and Drug Administration (FDA). However, poison centers, including the National Capital Poison Center, the Cincinnati Drug and Poison Information Center, and the Upstate New York Poison Center, all say the test kits contain such a small amount of sodium azide that most people will not become seriously ill if they come in contact with the chemical. 

“When swallowed, sodium azide can cause low blood pressure, dizziness, headache, and heart palpitations. In more severe cases, seizures, loss of consciousness, and death may occur. Sodium azide is a very potent poison, and ingestion of relatively low doses can cause significant toxicity,” the National Capital Poison Center explained. “Fortunately, the amount of sodium azide in most rapid antigen kits is much lower than the amount expected to cause poisoning if swallowed by an adult.” 

The two most common calls the Cincinnati Drug and Poison Information Center says it has received about at-home COVID-19 tests have been about children who ingested the liquid or adults who mistook the test bottle for eye drops. The National Capital Poison Center also said it has received calls from people who put the solution up their nose or spilled it on their finger. In each reported case, the poison centers say the person suffered no symptoms or they experienced mild irritation.

To prevent accidental poisonings from COVID-19 home test kits, poison control centers recommend the following tips:

  • Store the kit “up and away,” out of the sight and reach of children and pets.
  • Leave the kit sealed until needed and throw it away immediately after use.
  • Make sure to read and follow the instructions on the package before use. 

“If you suspect someone has swallowed sodium azide, do not make the person vomit. For eye exposures, rinse the eyes for 15-20 minutes with warm tap water. For skin exposures, rinse the skin well with tap water. If someone has swallowed part of a rapid antigen test and is choking, call 911 immediately,” the National Capital Poison Center explained.  

More from VERIFY: No, the CDC doesn’t count positive results from at-home COVID-19 tests


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