When working with large drivable milling machines (half lane and larger) on asphalt, concrete, and other materials containing silica, it's essential to recognize that this activity can produce respirable crystalline silica dust. Inhaling these small silica particles over time can result in irreversible lung damage.

To address potential exposure, WorkCover Queensland suggests the following controls in accordance with Appendix 4 of the Managing respirable crystalline silica in construction and manufacturing of construction elements code of practice 2022 (PDF, 1.71 MB):

Use suitable engineering controls

Consider the following engineering control options:

• For cuts of any depth in asphalt, utilize a machine equipped with exhaust ventilation on the drum enclosure and supplemental water sprays designed to suppress dust.
• For cuts of four inches or less in depth on any substrate, use a machine equipped with either exhaust ventilation on the drum enclosure and supplemental water sprays designed to suppress dust or a machine equipped with supplemental water spray designed to suppress dust (combined with a surfactant when used on any substrate).

Large drivable milling machines can be equipped with a combination of water sprays, exhaust ventilation, and surfactants to effectively control silica dust. The specific combination varies based on milling depth and substrate material.

Operate and maintain the machine to minimize dust emissions.

Select appropriate respiratory protective equipment (RPE)

The need for respiratory protective equipment (RPE) depends on:

• The chosen engineering controls.
• The duration of the task during the shift.
• The location of the work.

RPE is not required for the use of large drivable milling machines.