Most of the recent news regarding dust in construction has been in relation to OSHA’s hearings about a new proposed rule for respirable crystalline silica. As important as that rule is for reducing silica exposures for workers, this is also an opportune time to lower exposures for all kinds of dusts, including those commonly viewed as “nuisance dusts.”
“It’s just good practice to keep dust levels down on all jobsites,” says LIUNA General President Terry O’Sullivan. “Calling them ‘nuisance dusts’ can mislead workers into thinking these dusts are harmless, but all construction dusts present a real risk to a person’s lungs.”
Dusts with less than 1 percent quartz are considered inert, or “nuisance dusts,” but research over the last 20 years has shown that many, perhaps all, dusts previously considered inert can cause serious health effects. These low-toxicity dusts have been proven to cause pneumoconiosis, chronic obstructive pulmonary disease (COPD) and other nonmalignant respiratory diseases.
Some dusts may also contain other harmful substances including lead, asbestos and wood. Anyone who breathes in these dusts should be aware of the damage they can cause to the lungs and airways. The main dust-related diseases affecting construction workers are:
- Lung cancer
Most of these lung diseases take a long time to develop, so by the time workers are diagnosed, the damage is already done, making their health issues more difficult to treat. Some diseases like silicosis are irreversible. While the classic diseases of “dusty” occupations may be on the decline, they have not yet disappeared. Workers today still suffer from a variety of illnesses caused by dust inhaled in their work environments.
The table below summarizes some of the most common dust-related lung diseases:
Type of Disease
|Tungsten Carbide||Hard Metal Disease||Fibrosis|
|Moldy hay, straw and grain||Farmer’s Lung||Fibrosis|
|Droppings and feathers||Bird Fancier’s Lung||Fibrosis|
|Moldy sugar cane||Bagassosis||Fibrosis|
|Compost dust||Mushroom Worker’s Lung||No Fibrosis|
|Dust or mist||Humidifier Fever||No Fibrosis|
|Dust of heat-treated sludge||Sewage Sludge Disease||No Fibrosis|
|Mold dust||Cheese Washers’ Lung||No Fibrosis|
|Dust of dander, hair particles and dried urine of rats||Animal Handlers’ Lung||No Fibrosis|
* Fibrosis is the formation of excess connective tissue in an organ or tissue, often taking the form of scarring
The current permissible exposure limit (PEL) set by OSHA for total nuisance dust in construction is 15 mg/m3 as a time weighted average (TWA) for total dust. In construction, there is no established PEL for respirable dust – the particles small enough to get into the lungs. Research from the Institute of Occupational Medicine suggests that current occupational exposure levels are not sufficiently protective to workers. For this reason, new research recommends controlling respirable dust to 1 mg/m3 for all dusts, whether nuisance or otherwise.
Although not all dusts are combustible, in extreme circumstances, excessive dust can become combustible and lead to explosions. Keeping dust levels down helps protect workers from harmful dust and helps keep contactors in compliance with the OSHA PELs, but there are other additional benefits to controlling dust:
- Leads to good housekeeping, which sets the tone for a safer jobsite
- Promotes a clean/efficient jobsite
- Decreases downtime for dust cleanup (since workers are cleaning as they go)
- Can reduce the risk of damage to property from dust
- Creates better working conditions for all
- Protects the public from fugitive dust emissions
How can we protect the lungs from dust?
To avoid respiratory or other problems caused by exposure to dust, engineering control methods should be introduced. Some examples are:
- Use of wet processes
- Enclosure of dust-producing processes under negative air pressure (slight vacuum compared to the air pressure outside the enclosure)
- Exhausting air that contains dust through a collection system before emission into the atmosphere
- Use of vacuums instead of brooms
- Good housekeeping
- Efficient storage and transport
- Controlled disposal of dangerous waste
The use of personal respirators in dusty conditions can be vital to worker health, but it should nevertheless be the last resort of protection. Personal protective equipment (PPE) should not be a substitute for proper dust control and should be used only when dust control methods are not yet effective or are inadequate. Through education and training, workers must understand the need to avoid the risks of dust. They should be instructed to:
- When possible, avoid standing in any visible cloud of dust
- Position drills with respect to prevailing winds whenever possible and remain upwind of drill dust sources
- When using a respirator, follow directions and guidelines based on OSHA or MSHA regulations
In addition to a number of silica-related publications and programs, the LHSFNA’s Publications Catalogue also offers guidance on respiratory safety in Face It: A Laborers’ Guide to Respiratory Protection. This guide explains the respiratory protection standard and includes the full OSHA standard as an appendix.
The LHSFNA’s OSH staff is also available to assist contractors in creating and reviewing methods to effectively control dust on work sites. For assistance, call 202-628-5465.
[Travis Parsons is the LHSFNA’s Senior Safety & Health Specialist.]