300 Case study: EMS workers noise exposure from the environment and earphones, and its effect on auditory perception

What started out as an EHS incident report at Oslo university hospital, developed to be a master thesis as part of the master program in EHS at Norwegian University of Science and Technology. An EMS worker claimed to have been exposed to a loud noise in his radio earpiece, which caused him to rip it out while driving. Aiming to determine whether or not this claim could be true and to determine the most contributing source of noise in an EMS worker daily tasks, a study would be conducted at Oslo ambulance station, down town area. 200 dosimeter noise measurements was conducted, along with 30 around the clock measurements from different earpieces with the help of an artificial ear. In addition, 23 audiometry’s was performed before and after shift to check for temporary threshold shift in the EMS-workers auditory perception. The results still showcased that environmental noise was the most contributing factor with the majority of measurements above 130dBC. Noise from the earpiece would be abnormally loud, even on lower settings, also showing large differences between different earpieces with the “occlusion effect” being a major contributor. Also 20-25% of the employees had a temporary threshold shift of 10dB HL in the frequency’s 0.75, 2.0 and 4.0 kHz. From this study, actions have been made by the Oslo university hospital to lower noise exposure from both the environment and radio. Before actions were made, 20-25% of the EMS workers were at high risk of permanent hearing loss.