There are several different kinds of pressure-treated wood. The old bad stuff is CCA, which uses arsenic. It's been restricted (in the US) for about two decade

There are several different kinds of pressure-treated wood. The old bad stuff is CCA, which uses arsenic. It's been restricted (in the US) for about two decades, though still available for some applications. Home Depot does not carry it. The newer stuff is ACQ (several types) which are Al and Cu-based. Not considered toxic by the EPA, however some people (including myself) are still not comfortable using it for, e.g. garden beds. Sawdust of all woods is considered an irritant, toxic, and a possible carcinogen. Work outside, and/or use good dust collection. Always wear a dust mask.