Frank Crawley worked for ICI for 17 years as Plant and Commissioning/Start up Manager on Olefin Plants and "Special Duties Engineer" on Nylon Intermediates. During the latter he was won over to Loss Prevention by the late Trevor Kletz and also to HAZOP by the late Bert Lawley. After 10 years in the Offshore O & G Industry, retiring from BP, Crawley split his time as LP Consultant and Senior Lecturer in Academe. It was during his time in the O & G industry that he learned different ways in which the HAZOP tool could be used more, particularly the first "Drilling HAZOP" in UKCS some 33 years ago. This in particular revealed a number of deficiencies in the design of drill rigs which produced novel design changes. HAZOP has been his fascination and he believes that it is a very flexible tool which has more potential for development. Brian Tyler established his consulting company with his colleague Bob Simmons in 1990. At that time he was also on the staff of the chemistry department at the University of Manchester Institute of Science and Technology (UMIST).

His research work at that time focused on the areas of fire, explosion, self-heating and kinetics, including work on industrially related problems. By 1990 he had over 20 years' experience of organising meetings and courses under the general heading 'Safety in the Chemical Industry'. These included HAZOP and HAZAN, Fire and Explosion, Accident Investigation, Gas Dispersion and many others. His course "HAZOP study for team leaders and team members" is still run by the IChemE under the leadership of Phil Aspinall. Another major activity has been the authorship to two IChemE monographs. The first, written with Frank Crawley and Malcolm Preston, is 'HAZOP, Guide to Best Practice'; the second with Frank Crawley is 'Hazard Identification Methods'. In 2011 he was one of the first group elected to the newly established class of Associate Fellow of the Institution of Chemical Engineers.