OHS Code Explanation Guide

Published Date: July 01, 2009
Bookmark this page

Part 4 Chemical Hazards, Biological Hazards and Harmful Substances

Section 39 Use of crystalline silica in abrasive blasting

This section requires employers to make a conscientious effort to examine the use of less harmful abrasives when abrasive blasting. Employers must take into account technical, economic and availability factors. This section does not ban the use of crystalline silica in abrasive blasting.

The following are legitimate considerations in accepting or rejecting a less harmful substitute:

(a) technical – Can the substitute perform the same work and produce the same results as silica sand?
(b) economic – Is the cost going to be a prohibitive financial burden to the employer?
(c) availability – Is a sufficient supply of the substitute readily available?

Employers are expected to document their assessment of alternatives when deciding whether or not a silica substitute is reasonably practicable for a specific abrasive blasting job. Alberta Human Services is not looking for a detailed study for every situation where silica sand is used, but will be expecting an honest assessment and justification if silica is used.

In highlighting the use of crystalline silica in abrasive blasting, Alberta Human Services recognizes

(1) the hazardous nature of crystalline silica in its respirable particulate form,
(2) that abrasive blasting breaks silica sand down to respirable sizes, and
(3) process emissions are difficult to control.

The message to employers is this: “Use silica substitutes whenever you can. If you must use crystalline silica, understand your responsibilities and meet all regulatory requirements.”

Employers are reminded of the stringent regulatory requirements involving the handling of respirable crystalline silica in the workplace. Because of the low OEL for crystalline silica – respirable particulate: 0.1 milligrams per cubic metre for quartz vs 3 milligrams per cubic metre for particulate not otherwise regulated – the OHS Code’s comprehensive “restricted area” requirements apply, as does the need to have all workers wear respirators. Employers using crystalline silica for abrasive blasting are required to:

(a) establish a code of practice for their operations;

(b) ensure workers undergo required health assessments, paid for by the employer;

(c) establish a respiratory protection program for the proper selection and use of respirators;

(d) provide workers with and ensure they wear protective clothing and respirators;

(e) minimize the release of crystalline silica particulate into the air, keeping worker exposure as low as reasonably practicable, and never exceeding the OEL;

(f) keep the work site clear of any unnecessary accumulation of crystalline silica particulate and materials containing crystalline silica;

(g) ensure that decontamination of workers and materials does not result in the release of airborne crystalline silica particulate;

(h) provide a means of preventing contamination of workers’ street clothes;

(i) ensure only authorized persons enter a restricted area;

(j) post signs around restricted areas warning of hazards and ensure signs remain posted until the area is no longer restricted; and

(k) ensure workers decontaminate themselves prior to leaving a restricted area.

For more information
Crystalline Silica in the Workplace
Bulletin CH059