EWHC 520 (QB) 13th March 2013
Hill and Billingham v Lloyd’s British Inspection Services Ltd
Exposure to asbestos dust occurred in 1968. Was there a breach of duty?
HM Factory Inspectorate’s Technical Data Note (TDN) 13, issued in March 1970 was presented as representing the duty of care standard of around about that time.
The judge (Mr Bean) regarded the generally low background exposure to be irrelevant, focussing instead on showers of dust dislodged from overhead structures. He accepted that peak exposures of a few seconds duration would be at up to 100 f/ml.
Unfortunately, TDN13 includes express provision for such peak exposures. These are to be measured over a 10 minute period. Background level is critical to deciding what the 10 minute average would be.
Using basic physics (CFD would be preferred) the following estimates are made:
- If arbitrarily set at a maximum allowable 2 f/ml background, allowing 100f/ml exposure to persist for an unlikely 10 seconds and allowing a 10 minute diffusion effect, the average over 10 minutes would be 26f/ml. This would be in excess of the allowable exposure of 12 f/ml.
- But dust doesn’t just diffuse, it blows about (a point that was emphasised several times), the claimant might actually have moved out of the way of a shower of dust or moved a few feet away just because of the work he had to do. A combination of air movement and physical movement would be expected to return the dust concentration to background within 1 minute. The 10 minute average would then be 3.6 f/ml i.e… well below the duty of care threshold. To reach 12 f/ml the claimant would have to stand still in very still air for 4 minutes.
- TDN13 deals with repeated peak exposure events by insisting that the average exposure over any 4 hour period is below 2 f/ml. There is no way to estimate this without a background level.
So it seems TDN13 was adopted in principle, but not in practice. Given the data in the judgment, it seems unlikely there was a breach of duty in this case. Even with perfect hindsight the defendant would not have been expecting levels of exposure to be harmful.
Appeal allowed at up to 13th June 2013.