Pretty much everyone knows what PT stands for - pressure-treated lumber. Its familiar greenish color is everywhere exterior wooden structures are built. Did you know that one million decks are built in this country every year? It is a huge industry.

The wood is treated with a preservative to control damage from fungus, insects, bacteria and marine borers. The chemicals control wood damage and rot for many years. But if it's that toxic to the insects and rodents what is it doing to the carpenters and other trades people who routinely handle it?

The answer is that it can be very hazardous to people too. Here's why.

The most common way of treating wood to preserve it is by using a combination of copper, chromium, and arsenic metal salts. The wood is soaked in a pressurized water solution of these metal salts. Thus the name pressure-treated. This is why the wood is so wet and why painters debate whether to let it dry out and for how long, before coating it.

One of the ingredients, arsenic, sounds scary. We know it's poisonous. In fact, if it gets into our bodies (breathing, swallowing) it can cause cancer. Chromium can do the same thing. In addition, we know that continual contact with these metal salts causes skin irritation (dermatitis). A government study in the early 90's found that over half the carpenters on a large construction site reported skin problems, and those working exclusively with PT more often had dermatitis than those working only on concrete forms. Besides being carcinogenic and a skin irritant, exposure to these metals is also known to cause chromosome damage in men and women, thus possibly affecting construction workers' children. Other health effects, such as liver damage or digestive problems, are also possible. This is very toxic stuff!

Ok, so these hazards are in the wood. But how can they affect someone working with the wood? Since the metal salts are on the surface of PT lumber in significant amounts, they can get on our hands and skin. Splinters from PT can also cause skin ulceration and festering. And obviously they are in the saw dust created while cutting or sanding the wood, which tradespeople then breathe in.

If you are working with arsenic-containing PT and suffer short-term health effects such as headaches, dizziness and muscle spasms, or notice a garlic odor on your breath or feces, call the Occupational Health Clinic or your doctor. These are warning signs of overexposure. The symptoms will vary depending on the amount and duration of exposure.