Abstract: Employee #1 was cleaning in the hopper room on the textile production floor using a vacuum system and wearing a disposable dust-mist respirator. There was another worker in the hopper room but, because they were vacuuming on opposite sides of the large hopper, they were not always visible to each other. After a few minutes the coworker went to check the vacuum bag and found Employee #1 lying on the floor. He had suffered cardiac arrest. Investigation revealed that Employee #1 had mentioned to coworkers earlier in the evening that he had been suffering from heartburn for 3 to 4 days, and coworkers observed him taking an antacid (Rolaids). It was also learned that he had been suffering from numbness in his left shoulder and left arm. These are considered symptoms of cardiac distress. Employee #1 had been advised to leave work and seek medical attention, but he declined.