short answer - 'safe as houses'
Been involved (as HSE Manager) on sites to replace now dated 'metal checkers' dating many years.
Heavily pregnant women can use them no problem.
Theres usual hoops to jump through - to be extra brief, notification, prior R/A, monthly check for leakage.
Dead simple really and now pretty standard equipment for food manufacturing.

Most suppliers manuals are actually pretty good (Loma, Cintex etc etc).

Should all be in there.