why should I have to prove that it's harmful?
I haven't asked you to do that, I have asked you to show that anything (anything at all) has been proven safe. A poster up-thread put vaping in the same sort of category of risk as other everyday household chemicals. I'd agree with that. Have all your household chemicals been proven safe?
It's for the vaping industry to prove it's safe. And let's face it, their research isn't exactly disinterested, is it?
You haven't looked at the research that is posted on the UK govt. website have you? You haven't even properly read the BHF statement you posted. You haven't RTFT so you haven't read the statement posted here, signed by a fuck ton of public health orgs.
I understand your mistrust of research by the vaping industry. Until about 2014 all of PH thought the vaping industry was a cunning offshoot of Big Tobacco. It's not, it's mostly SME run by ex-smokers who want nothing to do with the tobacco industry and are sick to death of smokers (AKA human beings) being collateral damage in the war between Public Health and Big Tobacco. Vapers have crowdfunded their own research because they care about their health (weird, huh?) and have developed British Standards for the industry (they didn't have to, they just care about health - weird, huh?)
I'm not asking you to trust research that comes from the vaping industry though, I'm asking you to properly read stuff on the govt. website and a host of other properly reputable sources, including the one you provided.