Have you ever thought about the impact that dust in your workplace might have on your health? Dust isn’t just a minor annoyance. It can pose significant health risks, particularly in industrial settings.
In this post, we’ll examine the types of dust commonly found in industrial environments, the health risks associated with dust exposure, and practical methods for controlling dust to protect your well-being. By the end, you’ll have the tools and knowledge to ensure a safer, healthier workplace for yourself and your colleagues.
What You’ll Learn
- Types of Industrial Dust: Understand the different types of dust found in industrial settings and their sources.
- Health Risks of Dust Exposure: Learn about the potential health effects of exposure to industrial dust and how it can impact your well-being.
- Dust Control Strategies: Discover effective techniques and best practices for controlling dust and maintaining a healthier work environment.
Introduction
When evaluating the risk to workers’ health, it is important to consider the duration of exposure, frequency of exposure, and severity of health impact. In this post, we will discuss the significance of dust in industrial hygiene.
Silicaceous Dusts
Silicon is one of the most widely spread elements of the earth. Indeed, most of the rocks in the earth’s crust are silicates. The term silicate refers to compounds that are bound with silicon. Silicon dioxide is silica, which is the simplest form of silicon compound. It is also potentially hazardous, depending upon its physical configuration. Other types of silicates include naturally occurring minerals such as:
- Asbestos (used in building materials and for fireproofing)
- Clay materials such as bauxite
- Feldspar (a poetry glaze and abrasive material)
- Garnet (a precious stone for jewelry, also used as an abrasive blasting medium
- Magnetite
- Mica (has application as an electrical insulator)
- Olivine (used as an alternative to sand in foundry operations)
- Portland cement (used for making concrete and mortar)
- Soapstone (also known as massive talc or steatite)
- Talc (fine dust used in cosmetics, crayons, and wallpaper)
- Vermiculite (for paints and insulation).
These silica minerals combine silicon and oxygen atoms with other metals such as magnesium, iron, aluminum, calculation, sodium, and potassium.
Silicon Dioxide
Silicon dioxide, or silica, is the simplest of silicon compounds. From an industrial hygiene perspective, its physical structure can determine the significant risk to workers’ health. Silica exists in crystalline (free) and amorphous (non-crystalline) forms. Crystalline silica is further divided into five different symmetrical configurations or polymorphs.
Crystalline Silica
Quartz is the most commonly found form of silica that is stable at ordinary temperatures. It is widely distributed in the natural environment and occurs in granite, gneiss and mica, sandstone, and quartzite. It is also the main constituent of sand. Sand can be used in glassmaking, as an abrasive blasting medium, in metal polishing, and as a water filter in swimming pools. Mining is another potential source of exposure (Hwang et al., 2017).
Cristobalite, another form of crystalline silica, is stable at high temperatures. It is formed by heating quartz above 1150 C. While cristobalite is found less frequently in the workplace, it does present a greater risk to workers.
Heating crystalline silica between 870 C and 1470 C also produces tridymite. The final two types of crystalline silica are stishovite and coesite. All polymorphs of free silica are monitored as the respirable dust fraction.
Amorphous Silica
The characteristic of amorphous silica that differentiates it from crystalline silica is its random arrangement of silicon and oxygen atoms. Some examples of amorphous silica include:
- Diatomaceous earth (used to absorb liquids, for lagging steam pipes, and as a component of dynamite) – uncalcined diatomaceous earth is measured as the inspirable fraction, but if calcined, it may contain a significant proportion of silica, and exposure must be kept below the relevant national exposure standard for free silica
- Fumed silica (measured as the respirable fraction)
- Precipitated silica (nuisance dust that is deposited in the upper respiratory tract)
- Silica gel (a hydrophilic substance that is used to reduce humidity. It is a fairly innocuous substance and is sampled using the inspirable fraction).
Carbon-Based Dust
Exposure to carbon at work occurs either through pure carbon or carbon fixed to other elements, such as carbonates or hydrides. Pure carbon exists in two primary forms: graphite and diamond. Graphite is a grey, greasy substance that conducts electricity well and is used as a dry lubricant to manufacture electric motor brushes. For sampling, it is measured as respirable dust.
Diamond is used in the industrial setting for drills and abrasives due to its incredible strength and hardness.
Charcoal is often called amorphous carbon since it is a microcrystalline form of graphite. Carbon black is a commercial for carbon used in inks and as a filler for rubber. It is sampled as respirable dust.
Wood Dust
Industrial hygiene sampling for wood dust should be performed using the inspirable fraction. It is essential to understand the type of dust, though. Hardwood dust (those that are derived from broad-leaved flowering species, in the botanical group angiosperm, for instance, eucalyptus, teak, and silky oak) have a potential for adenocarcinoma and have a lower exposure standard. Certain types of hardwood are also sensitizers. Softwoods generally have a higher occupational exposure standard, although researchers have recently explored the risk of nasal and nasopharyngeal cancer from softwood (Siew et al., 2017; Beigzadeh et al., 2019).
Alkaline Dust
Alkaline dust (or bases) has a pH of more than 7. They can be used to maintain acidity balance and as filters, alloys in lead production, and cleaning agents. Some examples include:
- Calcium carbonate (occurs in nature as limestone, chalk, marble, dolomite, calcite, and oyster shells)
- Calcium hydroxide (also known as caustic lime, hydrated lime, or slaked lime)
- Calcium oxide (called lime, quick lime, unslaked lime, or burnt lime)
- Potassium hydroxide (also known as lye or caustic potash)
- Sodium hydroxide (caustic soda, soda lye, or sodium hydrate).
Organic Dust
Organic dust can be defined as dust from an organism containing carbon. The major outcome from exposure to organic dust is usually irritation; however, some individuals have an immunological response and may suffer changes to lung function (Bolund et al., 2017). For instance, cotton, flax, hemp, and sisal dust can cause irritation and an allergic lung disease known as byssinosis. Workers at risk include textile manufacturing, cotton farming, and ginning.
Other organic dust of industrial hygiene significance are:
- Tobacco
- Starch
- Sucrose
- Cellulose
- Grains.
Due to the dust’s high molecular weight, the health effects of exposure to this dust are irritant and, in some individuals, immunological in nature. For instance, confectionery workers are reported to have a decrease in pulmonary function, which is related to exposure to sucrose.
Summary
From an industrial hygiene perspective, the dust of significance includes silicaceous dust, carbon-based dust, wood dust, alkaline dust, and organic dust. Each has a different potential impact on workers’ health, and it’s important to understand exposure duration, frequency, and the nature of the dust to evaluate risk.
Helpful Resources
- Dust Exposure History Blog Post, by Megan Tranter
- Basics of Industrial Hygiene, by Debra Nims
Bibliography
Beigzadeh, Z., Pourhassan, B., Kalantary, S., & Golbabaei, F. (2019). Occupational exposure to wood dust and risk of nasopharyngeal cancer: A systematic review and meta-analysis. Environmental Research, 171(April), 170-176. https://www.sciencedirect.com/science/article/abs/pii/S0013935118306510
Bolund, A. C., Miller, M., Sigsgaard, T., & Schlünssen, V. (2017). The effect of organic dust exposure on long-term change in lung function: a systematic review and meta-analysis. Occupational & Environmental Medicine, 74(7), 531-542. https://oem.bmj.com/content/74/7/531
Hwang, J., Ramachandran, G., Raynor, P., Alexander, B., & Mandel, J. (2017). A comprehensive assessment of exposures to respirable dust and silica in the taconite mining industry. Journal of Occupational and Environmental Hygiene, 14(5), 377-388. https://www.tandfonline.com/doi/abs/10.1080/15459624.2016.1263392
Siew, S. S., Martinsen, J. I., Kjaerheim, K., Sparén, P., Tryggvadottir, L., Weiderpass, E., & Pukkala, E. (2017). Occupational exposure to wood dust and risk of nasal and nasopharyngeal cancer: A case-control study among men in four nordic countries—With an emphasis on nasal adenocarcinoma. Cancer Epidemiology, 141(12), 2430-2436. https://onlinelibrary.wiley.com/doi/full/10.1002/ijc.31015
