You have been in your job for a number of months and are settling in and enjoying the work. You start to notice that your direct supervisor and a couple of your older workmates regularly load up their trucks on a Friday with materials from the worksite.
Confront them and tell them that you know they are flogging stuff from the worksite and they should stop as it is illegal. Whilst this is the most direct way to call out poor behaviour and thievery there are some things for you to think about with the Step Forward approach in this instance. They may just make fun of you. They may threaten you and make your life difficult or they may try and bring you into the pilfering.
If your workplace has an HR Department, reach out and ask for a meeting. Before you meet with HR, write down what you saw– the date, the time, the place, the people, and exactly what you saw. Keep it until you are asked for it. You may not be asked for it as HR may do their own investigation so as not to put you at risk and to confirm what you saw. If your workplace doesn’t have an HR Department, identify a key person to report the issue to. It might be the Owner.
Do nothing, ignore what you have seen, and just do your job. This option may mean that you get dragged into the pilfering by association with your workmates and then you get accused when they are finally found out.