The Health and Safety Executive is meeting today to discuss the problem.
A study by Manchester Metropolitan University, which will be published next month, found the average level of radiation in caves was 2,900 becquerels per cubic metre. The National Radiological Protection Board recommends removing radon from homes if the level is above 200 Bq.
Radon comes from uranium in soil and rocks which decays to form radioactive particles. These can cause lung cancer. An estimated 2,500 people each year are killed by radon.
Researchers and the National Caving Association believe that although only a few people are at risk it is important that everyone is told of the potential dangers.
Forty caves were tested in the survey. The highest average yearly figure was 46,000 Bq for the Giant's Hole in Derbyshire - a popular tourist attraction.
Levels peak in summer when airflow is reduced. Some cavers spend hundreds of hours underground each year. Many are now reducing this and are being careful about which caves they use.
Robert Hyland, the report's researcher, said: 'We feel that individuals and organisations which take people caving have a moral obligation to inform those in their care of the risk from radon.'
The HSE is considering issuing safety guidelines.Reuse content