Or asbestos, which causes physical damage to cells which in turn may case cancer that leads to death. There are no bright rules. As a practical matter, I person

Or asbestos, which causes physical damage to cells which in turn may case cancer that leads to death. There are no bright rules. As a practical matter, I personally would draw the line between physical actions that are perceptible on a human scale (concrete blocking up the digestive tract, water blocking the lungs of drowning people) and "poisons" that operate on a smaller scale that we cannot see. Such an approach would include asbestos as a poison despite it doing only physical damage.