I Collect Robot Deaths

In 1981 Kenji Urada, a 37-year-old Japanese factory worker, climbed over a
safety fence at a Kawasaki plant to carry out some maintenance work on a robot.
In his haste, he failed to switch the robot off properly. Unable to sense him,
the robot's powerful hydraulic arm kept on working and accidentally pushed the
engineer into a grinding machine. His death made Urada the first recorded victim
to die at the hands of a robot.

There was another early robot-related death, in the US I think, where a robotic welder pinned a worker against a wall and the compression on his chest induced a heart attack.