5 The agreed statement of facts described the circumstances giving rise to the risk to safety as follows:
5.(a) The site has a number of risers being open shafts between floor levels which are designed for the installation and distribution of air conditioning, plumbing and other services.
(b) As a consequence of the risers travelling through a number of floors, penetrations through the floor of each level were required.
(c) Prior to the penetrations being opened up for the installation and distribution of air conditioning ducting, plumbing and other services, the penetrations were covered.
(d) The penetration covers at each floor at each riser were designed to prevent objects and water from falling between floors.
6.(a) Wideform constructed the penetrations in riser 4 in or around September 2000.
(b) The penetrations were covered as is industry practice for the reasons identified in paragraph 5(d) above.
(c) The design of the penetration covers however differed from usual industry practice.
7. The top of the penetration covers were trowelled to the same finish as the surrounding slab.
8.(a) Some but not all penetrations were initially marked with a painted outline and the word "peno" on the concrete floor.
(b) Contractors understood that the penetration covers were safe to walk on.
(c) DJD Masonry Contractors Pty Ltd adopted the approach to the penetrations that they were safe to walk on but not to load materials off.
(d) In riser 3 power outlets in common use were on the rear wall requiring workers to walk over the penetrations to access the power outlets
9. Some but not all penetration covers on site were fenced off.
10. The penetration covers on floors 7 and 10 were not fenced. These floors both had hobs built around the penetrations.
11. On 21 March 2001 Mr Brent Leadbitter commenced work at the site at approximately 7.00 a.m.
12. During the course of the morning Mr Leadbitter undertook his usual duties performing the laying of blocks on level 9 in company with other employees of DJD.
13. At approximately 10.00 a.m. that morning the DJD leading hand, Brian McMahon, had a conversation with DJD's contractor consultant from QMP, Nigel Jones and Jack Waitai-Tipene, the general foreman from Thiess Pty Ltd. That conversation occurred with all persons including Mr Waitai-Tipene standing upon the actual penetration cover on level 5 riser 4. This was directly below the penetration cover at level 6 which first collapsed. It was at this time that the exact method by which the holes were to be repaired was decided and directions given to the DJD Supervisor Brian McMahon.
14. As air conditioning ducts were being put through the riser 4 shaft it was determined that DJD would need to work from inside an adjacent area known as the smoke ventilation shaft to seal the shaft. This would require an employee of DJD to work atop scaffolding in the smoke ventilation shaft and replace blocks and seal with sealant into the smoke ventilation shaft wall.
15. From approximately 12.30 p.m. until 1.00 p.m. the DJD employees, including Mr Leadbitter, had their lunch break.
16. During or at the conclusion of the lunch breach Mr McMahon had a conversation with the DJD employees advising them of the requirement to undertake the work identified in paragraphs numbered 13 and 14 above.
17. The DJD employee, Richard Owen, was somewhat hesitant to perform the work and accordingly Mr Leadbitter volunteered to undertake the work. He was a short time later taken to level 9 to the top of riser 4 for a further briefing regarding his task by Brian McMahon his Leading Hand.
18. At approximately 1.30 p.m. Mr Leadbitter went to level 6 riser 4 and walked across a work platform covering the penetration cover on riser 4 level 6 and entered the smoke ventilation shaft adjacent and to the left of riser 4 through holes in the wall. The blocks that had been removed left a hole no less than 600mm high and approximately 600mm wide (certainly at no point less than 400mm wide).
19. Mr Leadbitter set up to undertake the rectification work atop scaffolding which had been installed inside the smoke ventilation shaft.
20. Mark Hopson, an employee of DJD and a qualified scaffolder was with Mr Leadbitter when he entered the smoke ventilation shaft over the work platform at level 6. Mr Hopson advised Mr Leadbitter that he was going to remove the work platform over the riser 4 level 6 penetration cover. He advised Mr Leadbitter that he should not attempt to exit through that area.
21. Due to the acoustics within the smoke ventilation shaft, Mr Leadbitter was able to give instructions Eg. Adjusting the position of his lead light hung from level 9 and to carry on a conversation with Richard Owen. Mr Owen was working on level 9 near the top of the shaft.
22. Mr Leadbitter found himself short of sufficient mortar to complete the job and asked Mr Owen to get someone to bring some down for him.
23. Mr McMahon, the leading hand, travelled down to level 6 with a wheelbarrow of mortar and set up two beams across the level 6 riser 4 area, in lieu of the work platform, and proceeded to pass a shovel load of mortar in to Mr Leadbitter.
24. Mr McMahon also left another half shovel of mortar outside the smoke ventilation shaft. Mr McMahon then returned to level 9.
25. Mr Leadbitter finished blocking in the hole on level 6 and then climbed down the scaffold to level 5 and exited the shaft there. Mr Hopson says he told Leadbitter that arrangements would be made for a ladder to be put up to him when he finished patching the holes. The work scaffold in the smoke ventilation shaft was topped by three planks. If the ladder was put up from a mid level already erected from level 5 it would have been too disruptive to the work required.
26. Mr Leadbitter then walked approximately 39 meters across the site to stair 3 up one flight and then a further 39 meters back to the riser 4 now at level 6. He then walked across the beams that had been laid by Mr McMahon over the penetration cover.
27. Mr Leadbitter scooped up a trowel of mortar and walked out onto the two 4 x 4 beams. He then smudged mortar over the rough edges left around the blocks he had just laid.
28. Mr Leadbitter performed a few trips doing this.
29. Mr Leadbitter then went up to level 9 to see Mr McMahon and checked whether or not he wanted him to joint seal the block work he had just completed. This course of action was agreed to by Mr McMahon although he did state that the application of the sealant should be done from inside the ventilation shaft.
30. Mr Leadbitter returned to Riser 4 level 6 with a caulking gun and walked on to the 4x4 beams and used the gun to joint seal around the blocks and has no further recollection after that.
31. One week prior to the incident Thiess had been informed by the defendant's employee, Mark Hopson, of a sag in the safety mesh on the bottom side (level 5 side) of the penetration for riser 4 on level 6. The penetration was sagged but intact. In addition to Mark Hopson, Brian McMahon was also aware of this sag.
32. The injured worker fell through the penetrations on Levels 6, 5 and 4, landing on Level 3. The penetrations collapsed under his weight.
33. The DJD normal tier of command included
(a) Off site Manager or Supervisor
(b) Nigel Jones - QMP Consultant
(c) Godfrey Peterson - Site Supervisor
(d) Brian McMahon - Leading Hand
34. The supervision structure in paragraph 33 above at this time was utilised to supervise only four men including Mr Leadbitter.
35. An inspection after Mr Leadbitter's accident identified that the penetration covers on levels 6, 5 and 4 of riser 4, had all been built with several pieces of non-interlocked mesh. Further, the mesh had not been embedded into the rear of the penetration hole. This was identified after the event by the manner in which the penetration covers were deformed.
36. As a consequence of sustaining injuries from the fall Brent Leadbitter had his right leg amputated below the knee.