OSHA Hazard Information Bulletins
Earth Boring Machines

June 4, 1990




  • Director
  • Office of Field Programs


  • Director
  • Directorate of Technical Support


  • Hazard Information Bulletin - Earth Boring Machines

The Directorate of Technical Support issues Hazard Information Bulletins (HIB) in accordance with OSHA Instruction CPL 2.65 to provide relevant information regarding unrecognized or misunderstood safety and health hazards, inadequacies of materials, devices, techniques, and engineering controls. HIB's are initiated based on information provided by the field staff, studies, reports and concerns expressed by safety and health professionals, employers, and the public. Information is compiled based on a comprehensive evaluation of available facts, literature and in coordination with appropriate parties. HIB's do not necessarily reflect OSHA policy.

The Boston Regional Office brought to our attention an accident involving an earth boring machine. This machine is a helical auger drill mounted on a truck. It is used for soil investigation and sampling. The auger drill involved in the accident was manufactured by the Mobile Drilling Company of Indianapolis, Indiana. The machine was not equipped with any guard or safety device.

The boring action of the machine was accomplished by a hollow-stem auger section connected to the drive shaft of the drill by an auger cap or bell. The bell was secured to the drive shaft by a bolt and a cotter pin. The bolt and pin used on the drive shaft of the machine involved in the accident protruded approximately 2 1/8" from the drive shaft.

The accident occurred when the injured worker's vest was caught by the cotter pin. The worker was then drawn into the rotating auger. He sustained multiple fractures and his right arm had to be amputated.

Because the driller and/or helper must have access to the auger area, a physical guard for the auger may be impractical. According to Mobile Drilling Company, the company has developed an emergency shut-off device with a trip cable to stop the drive shaft's rotary motion instantaneously. Drills manufactured between 1970 and 1980 can be equipped with the safety device as an option. Since 1980, the safety device became a standard equipment for Mobile Drilling Company's drills. Regardless of the manufacturer of an earth boring machine, it is feasible to protect workers from the hazard of rotating augers.

Please distribute this bulletin to Area Offices, State Plan States, and consultation Project Officers.