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Injury rates, ergonomic factors and work conditions associated with musculoskeletal injuries among school custodians in British Columbia
RS2003/04-020
Final Report Date: June 2007
| Principal Investigators: | Aleck Ostry (University of Victoria); Mieke Koehoorn (University of British Columbia) |
| Workplace Partners: | Union of Operating Engineers Vancouver School Board |
For more information about this project, please contact Dr. Aleck Ostry.
Issue
School custodian injury rates have been estimated to be up to four times greater than the school district average. The largest injury category for this group is musculoskeletal injuries (MSIs, sometimes referred to as sprains and strains). In order to better understand school custodian injury and MSI rates and how they are related to ergonomic risk factors and broader school environmental conditions, this project, using a cohort study design, examined the workplace injury experience of about 600 school custodians in a Lower Mainland School Board.
Key findings
- There were 11.3 injuries per 100 full time equivalent workers (FTEs), among custodial workers within the School Board between 2003 and 2006 which is over four times the overall injury rate for all occupations within the school district.
- MSIs made up 48% of all injuries, followed by slips and trips (22%).
- The tasks most associated with MSIs were cleaning floors, handling garbage, miscellaneous tasks such as helping a teacher, cleaning and moving furniture, miscellaneous cleaning, and moving lunch tables.
- Workers whose shifts involved the most pushing/pulling tasks (such as floor cleaning) had over five times the risk of MSIs compared with workers whose shifts involved the least amount of pushing/pulling tasks during their shifts.
- A higher risk of MSIs was also associated with working during the school year and working in schools with: grass fields (compared with gravel), portable buildings, and/or more hours of non-school rental use.
- The researchers recommend strategies to reduce the risk of MSIs for school custodians. They also identify key areas where new tools and approaches are needed to address higher risk tasks and working conditions.
Objectives
- To calculate injury rates among school custodians in the School Board, including separate analyses for the summer and school year
- To identify ergonomic risk factors (e.g., types of postures or lifting when performing tasks) and school conditions that are associated with an increased risk of MSIs for school custodians
- To develop recommendations for decreasing MSIs among these workers
Methods
This project was a cohort study using several sources of information to examine injury rates and MSI risk factors between 2003 and 2006 for about 600 school custodians employed by the School Board.
A Project Advisory Committee, with three school board and three worker representatives, provided advice to the research team on designing the study, collecting data, recruiting participants, and interpreting results.
Focus groups were conducted with custodians early in the project to gather input on working conditions, tasks performed in a typical work day for the main custodial occupational categories, and other school environmental factors (such as type of grounds surrounding the school, presence of elevators versus stairs, etc.) that participants believed might increase the risk of injury.
Ergonomic assessments were conducted by a trained ergonomist to gather data on how much bending, lifting, pushing/pulling and other ergonomic risk factors are involved in a typical work day. Assessments were conducted with a representative sample of 44 custodial workers, for about two to four hours each.
Injury data were gathered from incident reports of work related injuries filed with the School Board between 2003 and 2006.
A profile was created for each individual in the database that captured their estimated exposure to each ergonomic risk factor, school conditions, and the injuries experienced during the four year period.
Statistical analyses were conducted to determine custodial workers’ injury rates, MSI rates, and whether ergonomic risk factors and school conditions were associated with an increased risk of experiencing an MSI.
All data were used and reported in an anonymous format to protect the privacy of study participants.
Results
- The average injury rate for custodial workers within the School Board between 2003 and 2006 was 11.3 injuries per 100 full time equivalent workers (FTEs), which is over four times the overall injury rate for all occupations within the school district.
- Building Engineers had the highest rate (17.5 injuries per 100 FTEs).
- The overall injury rate was significantly higher during the school year compared with the summer season.
- Summer injury rates were 3.3 times higher in elementary schools than secondary schools – possibly due to custodial staff working alone and not having assistance with intensive summer cleaning tasks.
- MSIs made up 48% of all injuries, followed by slips and trips (22%).
- The tasks most associated with MSIs were cleaning floors, handling garbage, miscellaneous tasks such as helping a teacher, cleaning and moving furniture, miscellanous cleaning and moving lunch tables.
- Workers whose shifts involved the largest amount of pushing/pulling tasks (such as floor cleaning) had over five times the risk of MSIs compared with workers whose shifts involved the smallest amount of pushing/pulling tasks during their shifts.
- School conditions associated with increased risk of MSIs included grass fields, portables and higher school rental hours.
Recommendations
To reduce school custodians’ risk of MSIs, the researchers recommend:
- Alternating the higher risk tasks throughout the day (high risk tasks include cleaning floors, handling garbage, miscellaneous tasks cleaning and moving furniture, miscellaneous cleaning, and moving lunch tables)
- Ensuring Head Custodians and Custodians in elementary schools have assistance with heavy lifting and other demanding tasks during the summer. possibly by pairing custodial workers from different schools so they can work together on demanding tasks or having casual workers available to assist
- For schools with portables, considering lightweight equipment or storing equipment in the portables to remove the need for carrying heavy equipment between buildings
- For schools with grass fields, considering ways for occupants to remove mud from shoes, such as mats that remove debris and are easy to clean, before entering the school
Future directions
The researchers also recommend further research and development in a number of areas, including:
- Why Building Engineers have a significantly higher injury rate during the school year compared with the three other custodial occupation categories
- Best practices or standardized procedures for high risk tasks, particularly bending, lifting and pushing/pulling
- Alternative tools and techniques to prevent overuse, particularly for cleaning tasks and handling lunch tables
Publications and Presentations
Village J, Koehoorn M, Ostry A. Quantifying Tasks, Ergonomic Exposures and Injury Rates among School Custodial Workers. Ergonomics. In Press.
Injury Rates, Ergonomic Factors and Work Conditions associated with Musculoskeletal Injuries Among School Custodians in British Columbia (Final Report)
Presentation at the Association of Canadian Ergonomists Annual Conference in Banff, Alberta, October 23-25, 2006
Presentation to the Vancouver School Board and the International Union of Operating Engineers (IUOE), July 13, 2007