Quantifying tasks, ergonomic exposures and injury rates among school custodial workers

Abstract

A job exposure matrix of ergonomics risk factors was constructed for school custodial workers in one large school district in the province of British Columbia using 100 h of 1-min fixed-interval observations, participatory worker consensus on task durations and existing employment and school characteristic data. Significant differences in ergonomics risk factors were found by tasks and occupations. Cleaning and moving furniture, handling garbage, cleaning washrooms and cleaning floors were associated with the most physical risks and the exposure was often higher during the summer vs. the school year. Injury rates over a 4-year period showed the custodian injury rate was four times higher than the overall injury rate across all occupations in the school district. Injury rates were significantly higher in the school year compared with summer (12.2 vs. 7.0 per 100 full-time equivalents per year, p < 0.05). Custodial workers represent a considerable proportion of the labour force and have high injury rates, yet ergonomic studies are disproportionately few. Previous studies that quantified risk factors in custodial workers tended to focus on a few tasks or specific risk factors. This study, using participatory ergonomics and observational methods, systematically quantifies the broad range of musculoskeletal risk factors across multiple tasks performed by custodial workers in schools, adding considerably to the methodological literature.

Keywords:

• cleaning
• ergonomics assessment
• observational analysis
• custodian
• school

Acknowledgements

The authors would like to acknowledge WorkSafeBC's Finding Solutions for funding this work, as well as the support of the Vancouver School District and the International Union of Operating Engineers (local 963 Vancouver). Drs Koehoorn and Ostry were supported in part by Scholar Awards from the Michael Smith Foundation of Health Research. Dr Ostry is also a Canada Research Chair and receives salary support from that programme. The authors would also like to thank the workers who participated in the focus groups and the ergonomics assessments.