Talking about the ocean is odd, but there are towns in the UK (and most countries I’d assume?) where the natural level of fluoride is higher than the concentration they aim for when adding fluoride. I think that’s a pretty good argument for it being safe - the people of Hartlepool have been drinking fluoride rich water for 13 centuries and don’t have any noticeable issues compared to the rest OF County Durham.
Talking about the ocean is odd, but there are towns in the UK (and most countries I’d assume?) where the natural level of fluoride is higher than the concentration they aim for when adding fluoride. I think that’s a pretty good argument for it being safe - the people of Hartlepool have been drinking fluoride rich water for 13 centuries and don’t have any noticeable issues compared to the rest OF County Durham.