Evaluating the Effect of Training Along With Fit Testing on Premolded Earplug Users in a Chinese Petrochemical Plant

To gain insight into the current practice of hearing protection of Chinese workers and the value of hearing protection device (HPD) fit testing.

HPD fit testing was conducted on workers (N = 774) in a petrochemical plant in Eastern China who were on duty during the period of this study. The 3M E-A-Rfit Dual-Ear Validation System was used to measure the personal attenuation ratings (PARs) of a premolded earplug used at the work site. Repeated fit testing was conducted at approximately 6- or 12-month intervals. Wilcoxon signed rank tests were conducted to analyze the pairwise differences between the baseline, postintervention, and follow-up visit PARs, and Mann-Whitney tests were used to compare the PARs obtained by two follow-up groups.

The median PAR baseline was 11 dB; significant improvement was shown on the postintervention PARs (p < 0. 001). No significant difference was shown between PARs obtained during the 6- and 12-month follow-up visits (p > 0.05). Comparing PARs of follow-up visits with the baseline PAR demonstrated a significant improvement (p < 0. 001), but revealed a significant decline (p < 0. 001) comparing with the postintervention PARs.

HPD fit testing showed value added as to verify the sufficiency of attenuation. The training along with fit testing showed contributions to improve PARs, maintained effectiveness over time, and assisted in HPD selection. Follow-up is believed to be important to ensure that the HPDs are continually used correctly. There was no significant difference in the sustained effectiveness of the follow-up when observe 6- and 12-month subsequent to intervention.