In practice, there are many forces working against the
realisation of inherently safe design. For reasons of
efficiency and cost effectiveness, production plants, transport systems and other human designs have strived to
control hazards rather than excluding them altogether.
Furthermore, the dangerous element is often a fundamental part of the system, either as the very substance
motivating the system (e.g., nuclear power plants), or as in
other ways necessary for the system (e.g., fuel in various
transport systems). Focusing on the principle of inherently
safe design, however, has been a way of questioning the
‘necessity’ of many of these arrangements. For example,
even if gaseous nitrogen is needed for a process step, the
nitrogen bottles do not have to be located in the operators’
work area but can be moved outside, thus reducing the risk
of asphyxiation [5, p. 14–5]. Often, it is possible to replace a
hazardous substance with another, less hazardous one that
can do the job. Well-known examples include using helium
instead of hydrogen in balloons and reducing pesticide use
by changing agricultural technologies.