The most obvious freedom is from immediate bodily injury. Safety switches, gate, guards, etc. help provide this, as does proper trainingand well-designed processes.
Safety also includes freedom from chronic conditions that accumulate over time. This includes things like repetitive stress injuries, and long-term exposure to toxins.
The less commonly considered aspect of safety, though, is the freedom from stress.
There are real, scientifically proven health risks to having chronically high stress. Since stress and job satisfaction are closely linked, and since job satisfaction plays a large role in developing a continuous improvement culture, it follows that stress reduction and job satisfaction should have a prominent role in any safety program.
Most people familiar with Lean have heard of QDC (Quality Delivery Cost) as the core measurement categories. In less common but increasing use, you may see QDCSM (Quality Delivery Cost Safety Morale). This highlights the fact that people are becoming aware of the role safety plays in Lean.