airgap / negligent homicide charge

The determination of whether a failure rises to the level of negligent
homicide will require a review of industry standards, company standards and
sometimes straight common-sence.

If the industry standard is airgap re security you are probably okay so
long as you review and address the very concerns and questions you are
raising in a responsible fashion that does not rely solely on expediency,
cost, etc., but looks to real-world scenarios and emergency / backup
procedures, equipment, testing and training.

Mickey Fox
CMK Consulting Services

Here's a quote from a famous court case (T.J. Hooper) on liability and industry

    Indeed in most cases reasonable prudence is in face common prudence; but
    strictly it is never its measure; a whole calling may have unduly lagged
    in the adoption of new and available devices. It may never set its own
    tests, however persuasive be its usages. Courts must in the end say what
    is required; there are precautions so imperative that even their universal
    disregard will not excuse their omission.

And here's a quote from a legal textbook:

    The standard of conduct imposed by the law is an external
    one, based upon what society demands generally of its
    members, rather than upon the actors personal morality or
    individual sense of right and wrong. A failure to conform
    to the standard is negligence, therefore, even if it is due
    to clumsiness, stupidity, forgetfulness, an excitable
    temperament, or even sheer ignorance. An honest blunder,
    or a mistaken belief that no damage will result, may absolve
    the actor from moral blame, but the harm to others is still
    as great, and the actors individual standards must give way
    in this area of the law to those of the public. In other
    words, society may require of a person not to be awkward
    or a fool.

In other words, get real legal advice on the standard of care you should

If only that were more generally true.