Guidance

Sodium chlorate: general information

Updated 4 December 2024

Overview

Sodium chlorate is a colourless, odourless and crystalline solid. It is also known as chlorate of soda.

Uses of sodium chlorate

In the past, the main use of sodium chlorate was as a pesticide, largely to kill weeds and undesirable foliage. Sodium chlorate is harmful to both humans and the environment. Therefore, the sale and use of sodium chlorate in plant protection products and pesticides in the EU is banned. Such products may still be produced however, for transport and sale outside of the EU.

Sodium chlorate is also used to make other chemicals including chlorine dioxide.

How sodium chlorate gets into the environment

Sodium chlorate may be release into the environment during its production and use. It may also be released through use of old herbicide stocks.

Exposure to sodium chlorate

Despite being banned for use as a pesticide people may still have old stocks of sodium chlorate herbicide. This may be a source of exposure for the general population.

Exposure to sodium chlorate is more likely also occur in an occupational setting during its production and use.

How exposure to sodium chlorate could affect your health

Following exposure to any chemical, the adverse health effects by which you may encounter depend on several factors, including the amount to which you are exposed (dose), the way you are exposed, the duration of exposure, the form of the chemical and if you were exposed to any other chemicals.

Sodium chlorate is irritating to the skin, eyes and airways. The health effects of sodium chlorate exposure are from ingestion.

Within 2 hours of ingesting sodium chlorate there may be nausea, vomiting, stomach pain and diarrhoea. Ingestion may also lead to a condition called methaemoglobinaemia in which changes to the shape of red blood cells reduces their ability to deliver oxygen around the body. This can result in the skin becoming blue/grey, blood clots and damage to the kidneys. There may also be weakness, tiredness, dizziness, confusion, headache, mood changes, breathing changes, chest pains, fitting and coma. Symptoms may be delayed for up to 12 hours after the exposure.

Sodium chlorate and cancer

Sodium chlorate is not believed to be a cancer-causing chemical.

Pregnancy and the unborn child 

There are limited data available on the direct effects of exposure to sodium chlorate on pregnancy and the unborn child. Effects on the unborn child are more likely to occur if the exposure to sodium chlorate causes the mother to become unwell.

Children

Children exposed to sodium chlorate are expected to show similar adverse health effects to those seen in exposed adults. However, the effects are expected to be more severe in children as they are particularly susceptible to development of a condition called methaemoglobinaemia which can be caused by exposure to sodium chlorate.

What to do if you are exposed to sodium chlorate

You should remove yourself from the source of exposure.

If you have got sodium chlorate on your skin, remove soiled clothing (not over the head), wash the affected area with lukewarm water and soap for at least 10 to 15 minutes and seek medical advice.

If you have got sodium chlorate in your eyes, remove contact lenses, irrigate the affected eye with lukewarm water for at least 10 to 15 minutes and seek medical advice.

If you have ingested sodium chlorate, seek medical advice.

Additional sources of information

NHS Choices - Poisoning

Email chemcompendium@ukhsa.gov.uk if you have any questions about this guidance or enquiries@ukhsa.gov.uk if you have any other questions.

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