Du Pont is an obvious example. Many of the oil and gas companies listed under 'The Leadership Team' at this URL: www.stepchangeinsafety.net Since you're working on a board paper, it's worth thinking through answers to questions about the validity of the Safety Maturity model: the original research was done with BP before their heroics in Deepwater Horizon which challenges the validity of differences in outcomes (dependent variables) in relation to the inputs (independent variables) at Level3 upwards. Arguably, Reason's model of preventing organizational accidents allows much better scope for validation of the process and outcomes and may well be a much better bet if you're going to be accountable for loadsa money, or even a modest outlay.

Serious risks of citing any company as a 'Level 5' (or 4) are illustrated in the book 'Safety Performance in a Lean Environment. A Guide to Building Safety into a Process', P English, CRC Press, 2012 The author has plausible qualifications and corporate level experience as a safety practitioner and university lecturer ('associate professor' in the USA). Yet in his choice of Toyota as the main company to illustrate his arguments, he shows profound disregard for the collapse in driver safety care by Toyota, as the reviewer of his book in 'Ergonomics' made plain. When a company's safety system fails so badly, it illustrates how even well-honed procedures and state-of-the-art statistical controls are vulnerable - a reality commonly disregarded in the eulogies of 'safety maturity' and, unfortunately, of 'behavioural safety'. There are invariably some degrees of marginally controlled risks of harm in human enterprises, beyond nurseries which language like 'maturity' glosses over, as if the options are 'immature' or 'declining'.

Oh, and I should also have listed the Shell Pearl GTL construction project in Qatar. From what I've read and heard (not personal experience), that was clearly at level 5, and involved a multi-national construction workforce of 10's of thousands. Their OSH injury results were at least an order of magnitude better than London Olympics, and I don't believe the stats were fiddled. One factor in this was probably that all the workers were immersed in the project culture 24/7 as they were accommodated in camps. The contrast with recent construction sector data from Qatar is notable.