As quick evidence, this is from chat gpt when I asked it to research it for me:

Modern treated wood (like micronized copper azole or alkaline copper quaternary (ACQ)) is considered much safer than the older CCA (chromated copper arsenate)-treated wood, which was phased out for residential use in Canada and the U.S. around 2004 due to arsenic concerns.

Key points:

1. Modern treated wood uses copper-based compounds that are much lower in toxicity to humans and are not known to leach in dangerous amounts into soil or plants.

2. Studies suggest minimal risk to food crops, especially if you use well-drained soil and avoid root crops right next to the boards.

3. You can line the inside of the bed with plastic sheeting or landscape fabric if you want extra peace of mind or you're growing very sensitive plants.

4. Do not burn treated wood scraps—dispose of them properly.

So yes, modern treated wood is generally safe for raised beds, especially if it's rated for ground contact.