Many times contractors overlook the safety measures that need to be taken because they have a skilled staff that doesn't need to be micro managed. Additionally, they are poor examples themselves.
The truth is that safety does not have to get complicated, and when people really think of how easy (and inexpensive) it is to be safe compared to the cost of getting hurt, it should go without saying that it is the way to go.
The gear that anyone on a site should have access to are eye/ear pro and helmets. Those working on roofs need harnesses, and workers should have their own safety boots.
When it comes to eye/ear pro, anyone would be a fool not to wear them in a loud environment, or if they are using a saw. The long term effects are too costly, because a person will certainly lose his or her hearing after a few years of swinging a hammer, and there is no benefit to getting sawdust in one's eyes, much less a splinter that could cause blindness.
As a worker, the lost time on site could be very costly, especially if you are denied a disability claim, but for the contractor it is also terrible. Not only has someone you care about gotten hurt, but that can cause a delay on the job, which could back up other jobs. This hurts everyone because the house you were finishing ahead of schedule that was going to provide some cushion to allow you to over-staff some decks and porches just fell behind, meaning that a member of your crew is going to have to be laid off later, and that vacation you were planning isn't going to happen.
A great way to increase the competence of your team (and yourself) is to read up on safety. This could be as simple as having someone read the MSDS labels on the common products you use, or you could cycle your best people through an OSHA course.
In the US Marine Corps, combat engineers send their people through extensive training throughout their years of service. They are trained in HazMat, general construction safety, and the importance of their gear.
While we think of US Marines as always dealing with life and death situations, the truth is that many have non-combative roles, but they still take safety seriously. As a construction professional, you should as well.