Last reviewed 5 May 2022

The Building Safety and Construction Division (BSCD) of the Health and Safety Executive (HSE) has issued a safety alert with regard to mast climbing work platforms (MCWPs).

This is warning the industry of a serious technical fault that HSE has found with MCWPs which are used widely across construction projects. They can also be used in other industries for access and to maintain large plant.

“Platforms could fall from height where mechanical faults in drive units go undetected,” the BSCD said. “If not rectified quickly, the fault could cause serious injury, or even death.”

MCWPs, also known as “mast climbers”, can be used as an alternative to traditional scaffolding. They are comprised of a powered work platform attached to one or more vertical masts. The mechanical drive units are on the masts.

In construction, where they can be used to attach external components such as cladding, they provide both access and a platform from which to work on tall buildings.

However, some MCWPs, which rely on two independent motor drive units per mast as the means to prevent the platform falling with overspeed, are not fitted with suitable and sufficient controls to manage this risk.

Failures in drive units can be such that neither the centrifugal brakes (intended to limit the speed of descent) nor the automatic brakes (intended to engage when powered travel is stopped) within the drive units are able to have an effect.

Operators are advised immediately to check that the necessary control measures are in place for all MCWPs in use or available for use. The full text of the safety alert can be found at