The incident happened at an industrial unit on Lyde Green, in Cradley, at about 3.20pm Monday.
West Midlands Police said it is investigating the incident while the Health and Safety Executive has also been informed.
A HSE spokesman said: "HSE is aware of the incident and is carrying out initial enquiries alongside the police."
An air ambulance was sent to the scene yesterday but the man, who was in his 40s, was confirmed dead at the scene.
A spokesman for West Midlands Ambulance Service said: "We were called to reports of a medical emergency at an industrial premises on Lyde Green, Cradley at 3.13pm yesterday.
"Three ambulances, two paramedic officers, the Midlands Air Ambulance Critical Care Car and the Midlands Air Ambulance from Cosford attended the scene.
"On arrival we discovered one patient, a man, who was in a critical condition and already receiving medical attention from bystanders.
"Ambulance staff immediately took over and began administering specialist trauma care.
"However, despite everyone’s best efforts, it unfortunately became apparent nothing could be done to save the man and he was confirmed dead at the scene."