Is Pressure Treated wood safe for raised gardens?

its safe but be ready to change it quite often as wood rots easily next to soil unless you do one course of bricks to keep it of the soil and line the inside woth polythene.

Hi,
You don't say specifically where in the US you are, and depending on where you are the formulation of chemicals used to treat the wood is different.
Wood sold in most southern markets is more heavily treated, and wood sold in California has to be treated with only approved chemicals.
In answer to your question, treated wood can be used for raised beds, but it does have a "life" and will need to be replaced eventually, and because the wood does break down eventually, releasing the chemicals into the soil, most people do not want to use them when food will be grown.
Hope this helps!