In an ideal world, operators would not be exposed to a single molecule of a harmful substance; but, in the real world, this is simply not possible. However, should we actually be discussing exposure as opposed to containment?
An introduction to the risks posed and how the Hierarchy of Controls (detailed in most countries HSE including NIOSH) should influence our equipment selection criteria. The hierarchy of hazard control is a system used in industry to minimize or eliminate exposure to hazards. It is a widely accepted system, promoted by numerous safety organizations, and as standard practice in the workplace.