TDL, in the real world, the unions are very keen to see H & S standards upheld by the company, and in the real world they normally support management action when it is in relation to H & S because not to do so would be seen to condone poor H & S practices. Of course they will ensure that the management are not using it as an excuse to 'get rid of' a trouble maker.
If the management and unions won't stand up for H & S then this is a serious failing.
FYI I have live in the real world, and ground staff have been dismissed for such actions.