Combustion happens when a material reacts with oxygen and gives off heat. Sawdust is another material that is prone to spontaneous combustion, and the risk of spontaneous combustion from sawdust increases when doing refinishing work due to the presence of finish and possibly other volatile solvents in the sawdust.
Wood Allergies and Toxicity
| Wood Species | Reaction |
|---|
| Pine (Pinus genus) | irritant, runny nose, asthma |
| Pine, Huon | irritant |
| Pistachio | irritant |
| Poison Walnut (Cryptocarya pleurosperma) | bark irritating to skin, dust may cause asthma, nausea, giddiness, sap is toxic and corrosive |
The threshold in the case of the sawdust was at 260° C (500° F); at this temperature a slowly moving yellow flame about 3/4-in high spread from the pilot flame, markedly slowing when leaving the surroundings of the muffler/arrester simulator.
Wood dust is also associated with toxic effects, irritation of the eyes, nose and throat, dermatitis, and respiratory system effects which include decreased lung capacity and allergic reactions. Wood dust is also a safety concern because it can cause a fire or explosion.
It will depend on your city and what they accept in the various garbage collection programs, but in my area at least, saw dust can be disposed of in our "green bin" program along with other organic materials like food, small dead animals, etc. Many equestrian centers will welcome the dust and woodchips for bedding.
Here are some ways to keep it out of the trash bin:
- Make fake snow. Mix sawdust with white paint and glue to cover holiday crafts with simulated snow.
- Get a grip.
- Soak up spills.
- Feed your plants.
- Make a fire starter.
- Fill wood holes and defects.
- Pack a path.
- Chase away weeds.
Wood dust poses the following risks to worker health: Inhaling dust into the lungs can cause breathing problems and lead to lung diseases such as occupational asthma and lung cancer. Breathing in dust is the most common type of exposure to wood dust.
Sawdust isn't a better insulator for many kinds of jobs. Air cannot flow through styrofoam as easily as through sawdust, and so sawdust may have a greater convection component to its thermal conductivity than styrofoam.
DANGER: Oxygen-limiting silos may explode if water or foam is sprayed through the top hatch or if the hatch is opened.
Materials such as silica, limestone, sand, cement, fly-ash, etc., are inert materials in their pure form (i.e., these materials will neither burn nor support combustion and do not pose a risk of fire or dust explosion). Some materials will not present a dust explosion hazard due to their granular nature.
Flour and many other carbohydrates become explosive when they are hanging in the air as dust. Flour grains are so tiny that they burn instantly. When one grain burns, it lights other grains near it, and the flame front can flash through a dust cloud with explosive force.
Flour may seem harmless, but many people don't realize that it has a hot temper. Under certain conditions, foods like flour are highly flammable and can result in fiery kitchen situations.
Aluminum dust also can be combustible or explosive if it becomes suspended in the air at the right concentration. For example, one employee was killed, and three others were severely burned in an Indiana plant that manufactures aluminum automotive wheels after a series of explosions was fueled by aluminum dust.
Finely-divided lead dust or powder is a moderate fire hazard and moderate explosion hazard when dispersed in the air at high concentrations and exposed to heat, flame, or other ignition sources.
Sugar dust is thought to have ignited the blast, which claimed at least eight lives. Table sugar, or sucrose, is flammable under the right conditions, just like wood (which is made of cellulose, or lots of sugar molecules linked together).
Dust explosions occur when combustible dusts build up in the air and combust rapidly, causing a strong pressure wave to form. They are a deadly hazard in a variety of workplaces, from grain silos to plastics factories. A combustible dust at the right concentration level. Oxygen.
Explosions can occur in nature due to a large influx of energy. Explosive volcanic eruptions occur when magma rising from below has much dissolved gas in it; the reduction of pressure as the magma rises causes the gas to bubble out of solution, resulting in a rapid increase in volume.
Implement a hazardous dust inspection, testing, housekeeping and control program. Use proper dust collection systems. Regularly inspect for dust residues in open and hidden areas. If ignition sources are present, use cleaning methods that do not generate dust clouds.
OSHA defines combustible dust as "a solid material composed of distinct particles or pieces, regardless of size, shape, or chemical composition, which presents a fire or deflagration hazard when suspended in air or some other oxidizing medium over a range of concentrations."
Zinc Dust is Combustible and is an Explosion Hazard:Zinc is a lustrous bluish-white metal. It is a fairly reactive metal that will combine with oxygen and other non-metals, and will react with dilute acids to release hydrogen.
Conductive DustMetal particles such as Aluminium or Titanium that are deposited on equipment as dust layers and form as dust clouds in the local atmosphere.
If this dust cloud is ignited, a large, potentially devastating flash fire or explosion could occur. NFPA guidelines and the OSHA NEP state that a dust layer 1/32 inch (0.79 mm) thick spread over just 5% of the floor area of a facility is sufficient to pose a combustible dust hazard.
Chalk doesn't burn. A flammable liquid, such as ethanol, is filled into a small container. The liquid rises to the top of the chalk.
But here's the thing, there isn't anything explosive in custard powder, just the act of turning it into a dust cloud and igniting it in a small space made it explosive. Custard powder was invented in 1837 by pharmacist Alfred Bird.
What are examples of materials that can be a combustible dust hazard?
- agricultural products such as egg whites, powdered milk, cornstarch, sugar, flour, grain, potato, rice, etc.
- metals such as aluminum, bronze, magnesium, zinc, etc.
- chemical dusts such as coal, sulphur, etc.
- pharmaceuticals.
- pesticides.
- rubber.
- wood.
The dust also must be combustible. Some dusts, such as quartz sand or table salt no matter how finely ground will not burn because they are not combustible. Many metal powders will burn and could form explosive mixtures if suspended in air.
Fine bituminous coal dust is highly explosive when suspended in air. In a typical coal dust explosion, the dust is scoured by a small methane gas explosion, which also provides the initiating flame. The finer the coal dust and the greater the coal's volatile matter, the greater is its explosion hazard.
Wood dust becomes a potential health problem when wood particles from processes such as sanding and cutting become airborne. Breathing these particles may cause allergic respiratory symptoms, mucosal and non-allergic respiratory symptoms, and cancer.
Combustible dust is defined as a solid material composed of distinct particles or pieces, regardless of size, shape, or chemical composition, which presents a fire or deflagration hazard when suspended in air or some other oxidizing medium over a range of concentrations.
Other common symptoms associated with wood dust exposure include skin and eye irritation; nasal dryness and obstruction; and prolonged colds. The OSHA permissible exposure limit for nuisance dust is 15 mg/m3 , total dust (5 mg/m3 , respirable fraction) 8 hour time weighted average.
Yeah, it's toxic. Cost me a trip to the emergency room -- couldn't breathe after milling some cedar and then cleaning up all the dust -- the problem is exacerbated because sawing doesn't create "sawdust" but turns the stuff into a fine powder. Always wear a mask and cut cedar in a well-ventilated area.
