Those OSHA guidelines are for gaseous phase. Which yes you’re likely to get a high concentration even just pumping gas, but my guess is it averages out to within the limits. Seems weird to state liquid fractions.

Are you swimming in your fuel?

It’s simply trust in the organization that maintains the app.

Unless you’re coordination/organizing about legal grey or red areas then it’s not much danger. Meta says it’s E2E but do they really not have access to your data? I don’t believe them. Any data they have would be happily handed over to the authorities just like your protonmail.

Signal just straight up doesn’t have access since it’s all stored at the endpoint and they provide no remote backup.