Your mouth might temporarily taste soapy after you eat foods like carrots and cilantro. Carrots have a compound called terpenoids that cause this sensation. The soapy taste caused by cilantro is due to your genes and how the brain processes the smell. These foods may not taste good to you, but a soapy taste from either food isn’t cause for alarm.

However, when a soapy taste in your mouth lasts for several hours or days, it’s usually a symptom of overexposure to sodium fluoride. This condition may be serious. Here’s what to know about this chemical and how to stay safe if you work around it.

Read more: How your genes can lead to a soap taste »

Sodium fluoride is found in a variety of things, including toothpaste and drinking water. It can help prevent tooth decay and rebuild tooth enamel. It has been used in many public water systems since the 1950s. The low levels of fluoride found in toothpaste, dental treatments, and drinking water are generally safe.

However, high levels of sodium fluoride can be dangerous. This chemical is used in higher concentrations in insecticides and other industrial applications.

People who work with or around sodium fluoride on a daily basis are at greater risk of fluoride poisoning. You may also be at risk if a family member brings home contaminated clothing or other items.

People may have increased exposure risk if they work in the following fields:

  • agriculture (through insecticides)
  • mining and rock treatment
  • steel production
  • glass manufacturing
  • welding
  • electroplating
  • water treatment

Moderate exposure to sodium fluoride powder or crystals may cause:

  • skin irritation or burning
  • irritation of the eyes, throat, and nose
  • coughing
  • wheezing
  • shortness of breath

Along with a soapy or salty taste in your mouth, you might have the following symptoms:

  • numbness of your mouth
  • vomiting or diarrhea
  • abdominal pain
  • dilated pupils
  • paleness or blue tinge to the skin
  • spasms
  • collapse
  • shock

Fluoride poisoning may take anywhere from a few minutes to two hours to show up, according to the Food and Drug Administration. Call your doctor or get immediate medical help if you notice these symptoms. If left untreated, dangerous levels of sodium fluoride can lead to death.

The low levels of fluoride in dental products and drinking water are safe for most people. However, children who are younger than 2 years shouldn’t use fluoride toothpastes. They should be monitored around fluoride toothpaste and other dental products, such as mouthwash. Swallowing more toothpaste than what’s needed to brush your teeth can cause upset stomach, vomiting, or diarrhea.

In addition, watch for white, brown, or black spots on your child’s teeth. These may be a sign of too much long-term exposure to fluoride products during tooth development. Contact your doctor or dentist if you see spots on your child’s teeth.

Call your doctor if you have a persistent soapy taste in your mouth. At your appointment, your doctor will ask you about your symptoms and give you a physical exam. Be sure to tell them if you work around hazardous materials that might contain sodium fluoride or other chemicals.

Your doctor may also order lung function and urine tests to evaluate your level of exposure.

If you ingest a large amount of sodium fluoride, you should seek medical attention immediately. You should also call Poison Control at 1-800-222-1222 for further instructions.

Poison control may recommend eating foods high in calcium to help ease stomach discomfort for children who have swallowed too much toothpaste. Some foods to try include:

  • oranges
  • almonds
  • dairy products, such as cheese or milk
  • green vegetables, such as kale or broccoli

The risk of getting sick from sodium fluoride is more serious for people who work in an environment where they are exposed to the chemical. Short-term, acute exposure to sodium fluoride may give you symptoms such as a soapy taste in your mouth, vomiting, or shock. These symptoms should clear up with prompt treatment, so call your doctor as soon as you notice them.

Long-term exposure can give you chronic health issues, like bronchitis or fluorosis. The longer you are exposed, the more serious your risks become. There have not been long-term studies on this chemical’s ability to cause reproductive issues or cancer.

Stay safe if you work or find yourself around sodium fluoride. Follow these safety measures:

  • Keep fluoride-containing dental products out of your child’s reach.
  • Wear a respirator to protect your lungs. Wear other protective clothing like gloves and face shields to protect your skin.
  • Wash all clothing that has come in contact with sodium fluoride before wearing it again. Do not take unwashed clothing home — it may contaminate family members.
  • Do not eat, drink, or smoke in areas that might be contaminated.
  • Wash your hands before eating, drinking, smoking, or using the bathroom.
  • Wash any skin that has been exposed immediately to prevent burning.
  • Speak with your boss if you have workplace concerns. Ask about improving ventilation or isolating the areas where chemicals are stored and used.