Plywood is a common building material. Being cheap and plentiful, thousands of different applications exist, from home building to furniture building to shipping crate construction. A benefit of using plywood is that much of it is made out of fast-growing trees such as pine or spruce, which are easily replenished. However, plywood has some negative aspects you should be aware of so you can work with it safely.
When cut, plywood produces sawdust. This is common for all woods, not just plywood. However, plywood has its own unique hazard with sawdust. The glues used to make plywood are plastic compounds and more flammable than just wood sawdust. In its material safety data sheet on plywood, the Weyerhaeuser Corporation, a large manufacturer of plywood, noted that plywood dust is a combustion hazard if sufficient quantities become airborne. You should always practice good housekeeping to keep plywood sawdust to a minimum.
Glue Chemical Hazard
Many of the glues used emit formaldehyde gas. If you are a hobbyist who only occasionally works with plywood, this is not a significant hazard. However, a professional carpenter or builder is constantly exposed to plywood, and the gas can become a health hazard if allowed to build up in places such as unventilated warehouses. If you work with plywood constantly, wear a respirator to decrease the risk.
Treated Plywood Hazard
Outdoor grade plywood may be treated to prevent termite and rot damage. One treatment, chromated copper arsenate (CCA) causes known health hazards. First, arsenic is a known poison and can be absorbed through the skin. Sawdust from cutting CCA-treated plywood can be inhaled. Burning CCA-treated plywood releases toxins into the atmosphere. A professional carpenter who is constantly exposed to CCA may have a significant risk. The Wisconsin Department of Health Services recommends wearing appropriate safety gear, such as a respirator.
Combination of Hazards
The hazards combine in a cumulative effect. Sawdust, particularly from CCA-treated plywood, is both an inhalation and a fire hazard. Also, if you constantly handle CCA-treated plywood with bare hands, the arsenic can build up in your body along with the constant inhalation of formaldehyde gas. To prevent cumulative hazards, wear protective equipment for each hazard, such as a dust respirator, coveralls and gloves.