Do-it-yourselfers who like to build outdoor projects will probably feel more comfortable with new types of pressure-treated wood now that the arsenic has been eliminated, but there is still cause for caution.

Treated wood containing chromated copper arsenate (CCA) was phased out for residential use at the end of 2003 by agreement of manufacturers and the Environmental Protection Agency. The new versions of treated wood being sold at home centers and lumberyards contain preservatives such as alkaline copper quaternary (ACQ) and copper azole. The preservatives used for treating the wood make it highly resistant to termites and rot, so the wood is popular for decks, gazebos, lawn furniture, fences and other outdoor projects.

Users of the new types of treated wood will notice another difference: The price is higher than for CCA-treated wood, generally by about 30 percent. But it should not be assumed that the new preservatives make treated wood perfectly safe to handle and use. Manufacturers recommend the same precautions that were recommended for CCA.

The need for precautions might not be obvious. When I bought a couple of treated fence posts recently, I removed a tiny tag containing the price information and found, in extremely small type on the back, this information:

* Wear a dust mask, goggles and gloves when cutting or handling treated wood.

* After working with treated wood, wash exposed areas of skin.

* Do not burn treated wood.

* Do not use treated wood where it may come into contact with drinking water.

* Do not use treated wood where it may become a component of food, animal feed or beehives.

* Do not use treated wood for mulch.

Scraps of treated wood should be disposed on in a landfill or by burying them. Treated wood should never be used in a project in which untreated wood will serve as well, which covers many indoor projects.

If treated wood still sounds too scary to use, there are a few good alternatives. Cedar and redwood are among woods that are naturally resistant to rot, although both have become relatively expensive and redwood can be difficult to obtain.

For decking, many homeowners are turning to composite products made of ground-up wood and plastic. Composites often cost two or three times as much as treated wood, but have a number of advantages: They won't split or rot, don't have to be sealed or stained, and don't develop splinters. Some composites are available in colors that retain their original appearance for years. Composites do need periodic cleaning, however.

Still, I predict that treated wood will remain a useful and popular material. Those who want to try the new types will find a wide variety of outdoor projects at the Web site www.treatedwood.com. The project plans at this site include an Adirondack chair, rocker, deck, fence, garden bench, mailbox post, picnic table, trellis and more.

QOne of the walls in our wood-frame house has developed a baffling odor. The odor is strongest on sunny days when the sun shines on the wall. We have cleaned everything, but it didn't help. Any ideas?

AMy best guess is that a small animal, possibly a squirrel or mouse, has crawled into the wall and died. If this is the cause of the odor, it should disappear in time. In the meantime, you could try odor absorbers such as Nilodor (www.nilodor.com), sold at some pet stores and veterinarian offices.

One of my double-pane windows has fogged up between the panes. Is there any way to repair this and prevent it in other windows?

This is a common problem with older double-pane windows, and I know of no practical way to repair or prevent it. The seal between the two panes of glass springs a leak, letting moisture and dirt enter. The usual solution is to contact the installer or manufacturer and replace the defective part of the window.

Newer double-pane windows of good quality are much less likely to develop these leaks, and many manufacturers offer long-term replacement warranties. Be sure to check with the manufacturer or installer to see if your windows are covered by such a warranty.

Questions and comments should be sent to Gene Austin, 1730 Blue Bell Pike, Blue Bell, Pa. 19422. Send e-mail to doit861@aol.com. Questions cannot be answered personally.