Chemical plants (and other such facilities) should not be Internet connected. The equipment and tools should not even have a network stack.
Workers in such a facility should not have their general purpose phones and computers with them.
This is not a panacea - there are conceivable attack vectors for non networked equipment - but it raises the bar significantly and should be the bare minimum of acceptability for designing and running these plants.
Workers in such a facility should not have their general purpose phones and computers with them.
This is not a panacea - there are conceivable attack vectors for non networked equipment - but it raises the bar significantly and should be the bare minimum of acceptability for designing and running these plants.