HSE Warns on Health Effects of Slate Cutting

SLATE CUTTING AND DRESSING should always be done in a well-ventilated, monitored area to protect workers according to the Health and Safety Executive.

Exposure to silica particles small enough to breathe in, known as respirable crystalline silica (RCS) can cause life-threatening conditions, including silicosis, lung cancer and chronic obstructive pulmonary disease (COPD).

The research which looked at slate quarrying, found that while improvements had been made since the 1990s, there were still some exposure to RCS that wasn’t controlled, such as packing and stacking of slates after they have been split and dressed.

According to the report, it is known that long-term exposure to RCS at levels below the workplace exposure limit (WEL) still represents a risk to health.

Long term health effects

For roofers, the use of angle grinders is know to create greater amounts of fine dust than other methods of cutting and dressing slate.

The research states: “RCS has a WEL of 0.1 mg/m³, as an 8-hour time weighted average (TWA).

“There is no short-term (15-minute) limit and in these cases a figure of three times the 8-hour TWA limit is recommended as a guide.

“Uncontrolled long-term exposure to RCS can cause silicosis (a chronic irreversible lung disease) and lung cancer.

“The principles of good practice in Schedule 2A of the COSHH Regulations require measures to be applied proportionate to the health risk, therefore employers should reduce exposure significantly below the WEL because of the serious risk to health posed by RCS.”

The report itself is available here.




  1. Thank you for this. I’ve been telling my boys for years to make sure masks & goggles are on when cutting, now I have some proof for them that their health is at serious risk!

  2. You’re welcome HWRoofer. We are glad to hear you are getting the word out and taking your own and your team’s health risks seriously.


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