Originally Posted by
Greg R Bradley
PT lumber is all poisonous. The newer PT may not be as bad as the older PT that used arsenic. It could be worse! Just read the recommendations for handling, sawing, etc. and it should scare you badly.
Simply put, Glen, these comments are opinion, not facts, in practical, real-life use.
You should wear a dust mask. Same for redwood. You should not eat it. Same for plywood or OSB. You should not burn it. Same for plywood or OSB. Other than that, it is perfectly safe to use. This includes usage in gardens, but many people prefer not to do that. Certainly a legitimate choice, but not one backed by cold, sober, science.
In fact, the older, traditional treatment - CCA [chromated copper arsenic] disappeared from most retail stores [but not all] because of a classic tale of headline-driven emotion, marketplace maneuvering, and government bureaucratic inaction.
When the big hue-and-cry about the arsenic content was sweeping the nation some years back, everyone was in a big rush to judgement. It turns out that the chemicals in this process, like many, many others in other applications, must be reauthorized every 5 years by the EPA. That 5-year window was approaching. The big box fellers were stuck between a rock and a hard place. If they did not switch chemicals, they would risk being punished by the public because of the publicity. If one box switched to the higher-cost alternatives, they would risk being punished by the public, due to price differences in the store.
The elegant solution for everyone was for the EPA simply to not renew approval. This is not the same as ordering the product off the market. Voila! CCA is no longer approved, and everyone's costs and prices rose in unison.
As the emotional headlines faded away, the grinding scientific studies continued, and were eventually concluded. The result? CCA was perfectly safe.
Which helps explain the fact that you can, indeed, still buy CCA-treated lumber. Not at the big boxes, but at locations serving markets other than the DIYers. It was, and is, the single-best, cheapest, treating system for all applications. It is still approved for use in agricultural applications. It is still approved for use in wood foundations for residential housing. It is still approved for treating plywood. It is still approved for submersed applications [docks, seawalls, etc.] The alternate chemicals simply do not perform in those situations.
Cattle licking and chewing on CCA posts. Any home with PT plywood sheathing. CCA pilings sunk into the waters of our fisheries - I catch fish off the CCA dock of a friend's house in the Lower Potomac section of the Chesapeake Bay estuary, and eat 'em if they are big enough and dumb enough to hook themselves on my line. Vegetables from raised beds framed by PT lumber - even CCA. None of these scare me. None of these are hazardous to my helath.
Wear a dust mask. Don't eat it. Don't burn it. Not exactly the same as a toxic superfund site.
Facts are stubborn things.
When I started woodworking, I didn't know squat. I have progressed in 30 years - now I do know squat.