Wood dust - potential health risks and ways to reduce them

I chose this topic at the suggestion of a friend of the magazine whose health has been affected by spending a long time in an environment contaminated with wood dust. The topic was provocative, so I started documenting it. I found a lot of material related to health problems caused by wood dust, and the problems were also caused by the compounds in the wood, not just the dust itself. I have tried to summarize all this information and the result is below.

Sources of wood dust

Woodworking without sawdust and wood dust is inconceivable. No matter how efficient the dust extraction system is, there will still be dust. All machines that cut, mill and drill wood or wood-based panels are sources of dust even if they have dust extraction systems.

Dust also occurs in wood or panel sanding processes. The most harmful is hand sanding, and if the person sanding does not wear a mask, the risk of respiratory problems over time is very high.

Another big problem is the dust that is reintroduced into the system. It is the accumulated dust that is cleaned by processes that allow it to re-enter the atmosphere in the workshop. Specifically, when cleaning the workshop or department, no wet cloths or vacuuming systems are used, but it is simply removed from the places where it has been deposited. In this way it gets back into the air and is breathed in by those who work there.

Allergies and problems are studied with the idea that dust comes from wood that has not been chemically treated. If it is processed, the risk of substances to which the body reacts negatively increases. This is the case with biocide-treated wood (wood used outdoors) or wood-derived boards.

What prolonged exposure to wood dust can do. How this dust works

There are three ways dust acts on woodworkers:

• as solid particles that get into the nose, throat and lungs through breathing, direct contact on the skin or in the eyes;
• through the chemical compounds present in different wood species;
• by bacteria, fungi and mold in the wood.

Solid particles wood dust can cause skin and eye irritation, difficult breathing, dry and sore throat. Over time dermatitis, allergies, conjunctivitis, bronchitis or rhinitis may develop. Long exposure to dust can lead to occupational diseases.

The biggest problem is particles smaller than 1.3 microns, which are not retained by filters, not even high-performance HEPA (High Efficiensy Particulate Air) filters. They get absorbed into the body through the skin or lung walls and cause immunologic reactions. Hypersensitivity of the lungs may occur only during working hours and the symptoms can easily be mistaken for flu or colds.

Chemical compounds in wood can be very different. The fact that more and more exotic wood is now being worked with is the reason why various forms of allergies are emerging in woodworking. Some of the chemical compounds in wood are not even identified yet. The wood develops them as an adaptation to the environment in which it lives, to protect itself from insects in the area or to be more resistant to the weather conditions. These compounds are more concentrated towards the interior of the wood and that is why secondary processors are more exposed to diseases and allergies than primary processors.

But not all chemical compounds are unknown. Species belonging to the same classes have the same aggressive compounds even if they grow in different areas. For example, there are different species of rosewood or ebony that, even if they grow in different places, develop the same aggressive chemicals. Red cedar is another aggressive species, one of the most chemically aggressive. But also species that grow here, like nuc or maple, contain compounds that can cause allergies. To give you an idea here a list wood species from around the world and the problems they can cause.

Long-term contact with the chemical compounds in such wood species can lead to contact dermatitis, decreased lung capacity, pulmonary hypersensitivity or asthma as an occupational disease.

Often it's not the dust or chemical compounds in wood that cause allergies or respiratory illnesses but mold, bacteria and fungi growing on or in wood. It is recommended to use healthy, dry wood according to its subsequent use. If signs of infestation with micro-organisms are found it is best to avoid skin contact and to use protective equipment, both for hands, nose and mouth.

Controlled exposure lowers risk of disease

As I said, it is impossible to have a totally wood-dust-free environment when working in wood processing. But steps can be taken to minimize unpleasant consequences. Here are some of them:

• installation of high-performance exhaust systems in departments and workshops;
• using HEPA filters in exhaust systems to remove finer dust particles;
• purchase of tools and machines equipped with dust absorption systems;
• information on the species of wood used and its replacement where there is an increased risk of disease;
• choosing, where possible, designs that involve fewer operations that generate less wood dust;
• using sharp tools. Unsharpened or improperly maintained tools generate more dust;
• Maintenance of cleanliness in departments and workshops. Use methods that do not allow dust to re-enter the system: wet cleaning, dust vacuuming; daily cleaning so that dust does not accumulate;
• Avoid using compressed air to remove dust resulting from machining. Replace it with suction systems;
• wearing protective equipment with gloves and masks with high performance air filters;
• inform yourself about the risks of using certain exotic species. Study safety data sheets and attend safety seminars.

Exhaust systems, machines and tools with dust extractor

The way to minimize the amount of wood dust in the air and therefore the risk of becoming ill is to purchase exhaust systems that remove it from the workspace. These should be fitted with high-performance filters that allow as much dust as possible to be trapped as small as possible. In this way the air will be released into a much cleaner workspace or atmosphere and the risk of allergies and respiratory problems will decrease.

And machines equipped with suction nozzles right next to the cutting, drilling or milling tool are a very good investment. The immediate absorption of the dust and sawdust generated also prolongs tool life, which is another big advantage.

Sanding is a big generator of dust, both wood and varnish. While machines are equipped with high-performance vacuum cleaners, this is not the case for manual sanding. This is usually done in the workshop and dust removal is left to the exhaust system. A good investment in this case would be special sanding tables with dust extraction. The dust is removed as soon as it is generated, greatly reducing the risk of illness. I was once in a furniture factory in Bulgaria. They made special children's chairs for a Danish company. A lot of sanding was done by hand, but there was almost no dust in the production department, which was quite large. All the 15 to 20 sanding tables were equipped with vacuum extraction systems. The atmosphere in the hall was clean and the women sanding were not dusty from head to toe.

In conclusion

Don't neglect the wood dust in the workshop on the basis that in the past carpenters didn't have exhaust systems and nothing happened to them. They didn't have these tools that generate ever finer dust, and carpenters' bodies were not weakened by processed foods and an increasingly noxious environment. Nor were they working with species brought in from the far corners of the world.

There are also regulations on the amount of dust allowed in the working environment. Annex 32 of the General Rules for the Protection of Workplaces stipulates a limit of 5 mg dust/m³ air for both hardwood and softwood, but only 0.5 mg/m³ for cedar.

We live in times when allergies are increasingly common and unexplained reactions in the body are always occurring. A clean working environment can prevent us from further discomfort or even occupational illness. It is good not to ignore this.

Keep working and stay healthy!