If I was a labour organizer, I would explain the history of the problem, say being forced to work in unsafe conditions, and what steps the union had taken to address this issue with the company, the company's response to date and how the practice still persists and show what have been the consequences ie of lost time accidents including serious injuries and even fatalities. I would present this information in chronological order citing accidents which resulted in injuries or deaths and what action the union took and the co. response and then showing that entreaties to the co. have had no result so therefore the necessity of downing tools to demand real change in the companies behaviour.