OccuSafe Industrial Hygiene Consulting

OCCUSAFE CONSTRUCTION UPDATE
Monthly Round Up of Important Ideas and Standards in
Industrial Hygiene and Safety

April 2018

IN THIS ISSUE: Controlling Dust at Worksites

Many believe that dust generated by work and vehicle traffic at work sites is not a health hazard. Although dust or particulates are not hazardous materials, in large quantities they can damage the lungs. Small particles between 1 and 10 microns can be inhaled deep into the lungs and can be especially damaging. Both OSHA and the American Conference of Governmental Industrial Hygienists publish occupational exposure standards for total and respirable particulate.

The best way to control dust on job sites, especially during dry conditions, is to keep things wet. Some examples include:

• Use tank trucks equipped with hoses and nozzles that spray water or other dust suppressants over large areas to wet the materials disturbed during earthmoving, vehicle traffic, or other dust generating tasks.
• Assign a worker who assists the operator by applying water or other types of dust suppressants to materials being moved.
• Use large atomized misting devices.
• Attach spray equipment directly to a vehicle.
• Adjust nozzles so that water spray is directed at the work areas where dust suppression is needed.
• Use tools such as saws with built-in dust suppression.
• Add water to mixers so dust is not generated.

To confirm that dust is being controlled use a particle counter. This device uses a beam of light that is projected through the sample. If a particle blocks or scatters the light, it results in a measurable energy drop that is roughly proportional to the size of the particle.  A particle counter can be set to record average concentrations over the shift or over a shorter duration. It can also determine particle size to measure respirable particulates. The device can be worn by an employee to record personal exposure or set in a stationary location to take area samples.

Dusty worksites can be damaging to the lungs of workers. Employers should employ controls that keep particulates from getting airborne and help protect the health of their employees.