Pressure-treated lumber is perfect for a variety of applications. In construction, I’ve used it in everything from decks to fences to garden sheds. Its ability to resist decay, insects, and fungi while still retaining all the qualities of wood makes it endlessly useful.
However, exposure to pressure-treated wood can pose some risks to your health. Treated lumber contains chemicals. These chemicals preserve and protect the wood, but it means we come into contact with these toxins when we touch and handle the lumber.
In this article, I’ll discuss some of the risks associated with pressure-treated lumber and how you can mitigate them.
What Is Pressure-Treated Lumber?
First, let me explain that I don’t have anything against pressure-treated lumber. I believe it’s as important to a homeowner as household laundry bleach. But I feel it’s important to be up-front about its potential hazards.
Pressure-treated wood is wood treated under high pressure with pesticides and preservatives to resist rot, fungi, insects, and damage. This forces the pesticides and preservatives deep into the wood for long-term protection.
The most common pesticide used is chromated copper arsenate (CCA). It contains arsenic, which is highly toxic. The arsenic deters pests and fungi to preserve the wood. So, while pressure-treated lumber resists decay, it has dangerous chemicals you should be aware of, especially around children.
Toxicity Depends on Treatment Level
There are varying toxicity levels based on treatment type when it comes to pressure-treated lumber:
- Ground contact has the highest toxicity and the maximum amount of chemicals to resist moisture and pests. Don’t use this lumber in your home.
- Aboveground has a medium toxicity, best for aboveground use like posts and landscaping. It has fewer pesticides but isn’t completely chemical-free.
- Deck lumber has the minimum toxicity and is optimal for decks, playsets, and furniture. It has the minimum chemicals to resist surface fungus and pests. This is the only pressure-treated wood suitable for close contact.
How to Ensure Pressure-Treated Wood Is Safe
With knowledgeable safety practices, you can work with and use pressure-treated lumber responsibly and in your home. Here’s what you need to know.
Check lumber retention level stamps. Using treated lumber up to 0.25 is safe where skin contact occurs, like decks (you can learn about alternatives to treated lumber in our guide to decking). Only use treated wood above 0.25 for fence posts and structures with limited contact.
Don’t use pressure-treated wood for food containers or cutting boards. Even playsets should get a protective sealant.
Be careful when working with pressure-treated wood. Cover up skin with gloves and protective clothing. If you’re sanding, wear a respirator and goggles. Be sure to wash clothes exposed to treated lumber separately. Avoid burning pressure-treated wood.
An oil-based primer followed by one to two coats of protective sealant is ideal for limiting pesticide exposure from skin contact, dust, or rain leaching chemicals out over time. Make sure to use sealants labeled as safe for pressure-treated lumber.
Environmentally-Friendly Alternatives to Pressure-Treated Wood
Consider these eco-friendly wood options:
- Rot-resistant woods like cedar, redwood, and cypress naturally resist moisture and pests minus chemicals. They cost more but last decades.
- Non-arsenic treated wood uses less toxic pesticides, though availability can be spotty.
- For decking, railing, playsets, and patio furniture, plastic or composite lumber contains no toxic chemicals yet resists moisture and decay for decades with minimal care.
So, Is Pressure-Treated Lumber Safe at Home?
Pressure-treated wood containing arsenic carries risks but can be managed safely with careful precautions. Purchase residential-use lumber, work outdoors with protective gear, seal projects to limit exposure, and wash after handling. Also, supervise children and teach them not to put the wood in their mouths.
With informed handling, pressure-treated wood resists rot for decades at a budget price. But remain aware of its toxic chemicals and use safer alternatives whenever possible.Â
FAQs About Pressure-Treated Lumber
Does sealing contain chemicals?
Sealing solutions provide an additional barrier but don’t fully contain chemicals like arsenic. Still, practice safe handling and washing when sealing.
Does weathering eliminate chemicals over time?
Some minimal leaching may occur after many years of outdoor exposure. But the chemicals permeate deep within and cannot quickly break down through weather alone. Assume wood always remains toxic.
Can sealed pressure-treated wood contact edible garden plants?
Chemicals can potentially leach into soils, so treated wood shouldn’t directly contact fruits, vegetables, or other food crops. Use naturally rot-resistant wood or composite plastic lumber for garden bed structures instead.
Is it safe to reuse reclaimed pressure-treated wood?
Reclaimed pressure-treated wood may appear weathered but still contains high pesticide levels in its core. Don’t reuse this wood for furniture, decking, playsets, or any structures allowing skin, clothing, or food contact. It’s safer to discard old pressure-treated projects appropriately.