In fact, the use of personal protective equipment (PPE) is blatantly violated. None of the companies studied has a safety officer on site. ... 16-24. 666 Aliyu A.A, Shehu A.U., 2006, Occupational hazards and safety measures among stone quarry workers in northern Nigeria, Niger Medical Practitioner, 2, 42-47. Arewa A.O., Farrell P., 2012, A ...