Coldlime, CCA has been used to pressure treat lumber since the 1940s. Since the 1970s, the majority of the wood used in outdoor residential settings has been CCA-treated wood. Pressure treated wood containing CCA is no longer being produced for use in most residential settings.

That said, people do it all the time. You'll have to decide for yourself. Below is a link to an article that may be of help to you in deciding. There have been many discussions here at gardenweb on this subject. You can do a gardenweb search on "pressure treated lumber" if you'd care to read some of those.

One last thing...there is a vegetable gardening forum here at gardenweb. If you post this query there, you'll get a lot more responses than you will here.

Here is a link that might be useful: Does Pressure-Treated Wood Belong in Your Garden?

Hi Coldlime,
My "significant other" built 2 lovely raised beds, using CCA timbers, 2 years ago this fall, so this was our second year using them.

He used 2-10' x 12" timbers for each box, then stacked the boxes 2-high so we don't have to bend over so far for harvesting! The secret to our success was that he was able to obtain some over-sized pieces of REALLY heavy duty black plastic, with which he lined each 2-high grow-box (including the whole bottom). Weeding?? No weeds at all, thanks to that same black plastic.

We have grown chilis, Roma tomatoes, lettuces, spinach, beets, cucumbers...no leeching nasty chemicals from the CCA wood OR the plastic liner. "He done good!"