Complying with OSHA Control Table 1 Does Not Guarantee Worker Protection

Queensland has adopted the OSHA silica control table as part of a new construction code of practise. The table mandates dust extraction and water suppression systems, and the use of RPE depending on the activity and duration.

No validation (exposure monitoring) is required if the controls are implemented. The implication is that workers would be adequately protected, that is below the 50ug/m3 exposure standard, provided that the controls are implemented.

You may be sceptical that, given the variety of tools and control systems available, the level of protection offered by these controls would vary considerably. A recent study has shown that exceedances are still possible despite the implementation of the mandated controls.

Percentage of samples greater than 50ug/m3 on average during the task with mandated controls.
Grinding – 80%
Cutting – 40%
Dowl drilling – 40%
Core drilling – 0%
Jackhammering – 0%

There is plenty positive to say about the control table - Similar dust controls have shown to reduce exposures as drastically as 93%. Unsurprisingly these controls do have a significant impact on dust levels. And the simplification of control implementation offered by the table would likely increase compliance within the construction industry.

HOWEVER!

Control validation such as exposure monitoring should be conducted regardless of the table's requirements.

Implementation of temporary controls such as RPE and the investigation of control improvements should be conducted regardless of the table's requirements.

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Reference
Cothern et al. (2023). The evaluation of worker exposure to airborne silica dust during five OSHA table one construction tasks. Annals of work exposures and health. 67, 572-583.

Footnote - the paper has its faults, but this doesn't detract from the overall findings. They also found, unsurprisingly, that enclosed vs open environments played a major role in the concentration levels.