Be aware: That COVID-19 test kit in your home could contain a toxic substance that may be harmful to your children and you. The substance is sodium azide, and Cincinnati Children's Hospital Medical Center's Drug and Poison Information Center has seen a surge in calls about exposures to the chemical since more people started self-testing for COVID-19 at home. Fifty million U.S. households have received some version of the test kits, although it's not clear how many contain sodium azide. The government has sent 200 million of the kits, with about 85% of initial orders filled. The chemical is colorless, tasteless and odorless, and it is mainly used in car airbags and as a pest control agent. Ingesting it can cause low blood pressure, which can result in dizziness, headaches or palpitations. Exposure to it can also cause skin, eye or nostril irritation. Large amounts of exposure to sodium azide can cause severe health threats, leading to convulsions, loss of consciousness, lung injury, respiratory failure leading to death, the Centers of Disease Control and Prevention notes. "Sodium azide is a very potent poison, and ingestion of relatively low doses can cause significant toxicity," Poison Control said. "The extraction vials do look like small squeeze bottles. Some people may accidentally confuse them with medications." Several poison centers throughout the United States have reported sodium azide exposures from the COVID-19 test kits.