Respirable Crystalline Silica

The HSE have recently released updated guidance on health surveillance for workers exposed to silica dust that can be breathed in. This is known as respirable crystalline silica or RCS. RCS can lead to a number of health problems including silicosis and chronic obstructive pulmonary disease (COPD). Silica exposure is also linked to lung cancer.

Whilst silicosis was previously a serious problem, improved workplace conditions and, in particular, prevention of dusty working has seen the condition mainly disappear. However, many workers are still exposed to RCS and whilst most exposures tend to be below the Workplace Exposure Level (WEL) there is still a risk of health problems, particularly if exposed to RCS over many years.

The new HSE guidance requires employers to make their own assessment if employees might be exposed to RCS and, if necessary, to carry out health surveillance including chest x-rays. The chest x-ray can detect the first stages of silicosis before it affects breathing or causes symptoms so it is a useful test. Modern chest x-rays involve very little x-ray exposure and can be carried out relatively cheaply.

Based on the HSE guidance and the scientific literature, our recommendation is that you should consider health surveillance for anyone who is exposed to RCS where this can be detected through exposure monitoring, even when this is below the WEL which is 0.1 mg/m3 of RCS.  Even at 10% of the WEL, research suggests that there is a 2% chance of developing silicosis over a lifetime working at this exposure level.

Where employees are exposed to RCS they should at least have annual health surveillance including a health questionnaire and breathing test.

We recommend that any workers exposed to RCS should have a chest x-ray. Providing the routine health surveillance remains satisfactory, another chest x-ray should not be necessary for up to a further 15 years.

After 15 years of exposure, we recommend a repeat chest x-ray is carried out at least every 3 years.

The most important thing is that if your workers might be exposed to RCS you must carry out exposure monitoring. This will determine whether you need to take any action to control exposures and whether you need to do any health surveillance.

If you would like further advice about silica and health surveillance and chest x-rays we would be pleased to help.

HSE advice on silica can be accessed at:

For more information contact us on 01284 247040 or email