Injuries from slips and trips in construction

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Applied Ergonomics 37 (2006) 267–274 www.elsevier.com/locate/apergo

Injuries from slips and trips in construction$ Hester J. Lipscomba,, Judith E. Glaznerb, Jessica Bondyb, Kenneth Guarinic, Dennis Lezotteb a

Division of Occupational and Environmental Medicine, Department of Community and Family Medicine, Box 3834, Duke University Medical Center, Durham, North Carolina 27710, USA b Department of Preventive Medicine and Biometrics, University of Colorado School of Medicine, Denver, Colorado, USA c OMI Safety Services, Inc., Denver, Colorado, USA Received 22 February 2005; accepted 25 July 2005

Abstract Construction injuries preceded by a slip or trip were documented using data from the building of the Denver International Airport (Denver, Colorado, USA), the largest construction project in the world at the time. Slips and trips occurred at a rate of 5/200,000 h worked accounting for 18% of all injuries and 25% of workers’ compensation payments, or more than $10 million. Slips contributed to the vast majority (85%) of same-level falls and over 30% of falls from height, as well as a significant number of musculoskeletal injures sustained after slipping or tripping but without falling. The injury burden would have been under-recognized in analyses of most coded compensation records. In contrast to other types of injuries, the most common contributing factors were environmental in nature including conditions of walking and working surfaces, terrain and weather. Due to the very dynamic nature of construction work, reducing slips and trips will require a focus on environmental and organizational solutions that evolve as the site changes and the construction project evolves. r 2005 Elsevier Ltd. All rights reserved. Keywords: Injury epidemiology; Slips; Trips; Construction workers; Text analyses

1. Introduction Slips and trips are recognized as significant occupational safety problems (Leamon and Murphy, 1995; Kemmlert and Lundholm, 2001; Layne and Pollack, 2004). Surface contaminants and physical hazards that contribute to these events include slick or uneven surfaces, inclines, stairs and ladders (Bentley and Haslam, 2001; Chang, 2001). Human factors, such as movement, performance and speed of work tasks, and carrying are increasingly being recognized for their potential contributions to injuries from slips and trips (Courtney et al., 2001a). Courtney et al. (2002) have documented significant work disability in the construction trades secondary to slips and trips, particularly for contusions and fractures.

$ Grant Sponsor: National Institute for Occupational Safety and Health; Grant number: 0R01 OH003613. Corresponding author. Tel.: +1 919 286 1722; fax: +1 919 286 1620. E-mail address: [email protected] (H.J. Lipscomb).

0003-6870/$ - see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.apergo.2005.07.008

A number of factors may place construction workers at particularly high risk for injury from slips and trips. The work environment in construction is by nature dynamic; occupational exposures change as the project progresses. A number of different trades are typically present on site simultaneously, often performing tasks in close proximity, and potentially creating hazards for one another. Manual materials handling is common in construction and often involves carrying, pulling, or pushing large, heavy objects that may obstruct the workers’ view. As stairs and surfaces are being built they lack the recommended surfacing and railings, and as such can present hazards to workers. Construction work is performed outdoors and indoors throughout the year, as well as in transitional environments as structures are being erected and closed in. To get to their personal work area workers navigate the evolving site. Construction sites are notorious for generating debris throughout the building process. Debris includes construction materials as well as dusts from materials like wood, fireproofing and drywall. Although working surface guidelines suggest 0.5 static coefficient of friction levels

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(American Society for Testing and Materials, 2002), contamination of surfaces with dirt, dust and mud from outside is difficult to control. We document construction injuries preceded by a slip or trip and their associated workers’ compensation payments using data collected in the building of Denver International Airport (DIA; Denver, Colorado, USA). Built between 1989 and 1994, DIA was the largest construction project in the world at the time and involved a wide variety of types of construction work. Text data from injury reports and investigations conducted at the time of the injury provided an understanding of factors contributing to injuries from slips and trips that can help in developing ways to prevent these injuries. 2. Methodology 2.1. Data available for analyses 2.1.1. Administrative data In the building of the DIA, 2843 contracts were awarded to 769 contractors without pre-qualification based on prior health and safety records. Over 32000 employees worked on the project. An Owner Controlled Insurance Program (OCIP) provided workers’ compensation and liability coverage for the project and an onsite medical clinic and physician referral system managed the 4634 injuries or illnesses sustained. The workers’ compensation data contained information on the date of injury, the nature of injuries, body part involved and the broad construction domain where each injury occurred such as site development, roadway or airfield construction, or building. Contractors reported monthly payroll and job classification based on National Council of Compensation Insurance (NCCI) codes. These job classifications define specific types of work, such as iron and steel erection under three stories or concrete construction, rather than types of workers or trades. The methods used in the analyses of injury experience and payment rates on this project using these administrative data have previously been described in detail including methods used to convert payroll to estimates of hours worked (Glazner et al., 1998; Lowery et al., 2000). 2.1.2. Text data In addition to administrative data, text descriptions from 4143 First Reports of Injury (FRI) associated with the filing of a workers’ compensation claim and 1808 accident investigation reports (AIR) completed by onsite safety personnel or supervisors at the time of injury were available. These text descriptions were imported into a qualitative software package (N5) (QSR International Pty and Ltd., 2000) designed for coding, cataloguing and searching of text data. Basic information on the type and nature of injury, as well as the initial energy exchange leading to injury, or mechanism of injury event (MOIE) were coded from text descriptions when available. For this

analysis we were interested specifically in injuries that were preceded by a slip or trip. The records showing that a slip or trip preceded the injury were further assigned to subcategories designating whether the injury was the result of a fall from height, a fall on the same level, or no fall. Factors determined to contribute to the injury were categorized using a modification of Haddon’s matrix (Robertson, 1998) designed to distinguish contributions of agent, human, environmental, and organizational factors. Agent factors were used to code contributions of tools, equipment, or materials including instances where the injury appeared related to the size or weight of the object, for example. Human factors included behaviors or characteristics of the injured worker or co-workers that contributed to the injury event and included such things as infraction of safety rules, fatigue, or inexperience. Factors related to the environment included weather (wind, ice, snow, mud), conditions of walking/working surfaces as well as those related to outside terrain. Poor housekeeping, lack of appropriate equipment for the task, and staging of materials were among those considered to be organizational in nature. A single reviewer examined all available text reports for each injury to code basic information on body part injured, nature of injury, and a single MOIE. Incidents resulting from the same MOIE (slips or trips in this case) were then grouped together for a second review focused on contributing factors. The contributions to injury, which we felt were more open to interpretation, were coded by two research assistants working independently. The coders compared their assignments and tried to resolve discrepancies. When this was not possible, the report was referred to the investigators (JG, JB). Remaining concerns were referred to a member of the research team who had been Manager of Safety on the DIA construction site (KG). 2.2. Data management and analyses The codes assigned to the text description for each injury were exported to SAS Version 8.12 (SAS Institute and Inc., 1999) and merged with the administrative data; the administrative variables were likewise exported to N5, so that both the qualitative and quantitative packages contained both the administrative and text-derived data. After merging the text and administrative data, descriptive statistics were generated on the breakdown of slip/trip injuries by mechanism of injury (no fall, fall from the same level, fall from height) and by nature of injuries sustained and body parts injured. The construction domain (e.g., site preparation, roadway, airfield, building construction, etc.) in which the injuries occurred was also analyzed. Overall injury rates, rates by MOIE and for specific types of work were calculated per 200,000 h worked. The rates of slip/trip injuries were calculated by month of the calendar year to assess seasonal variation. Confidence intervals for rates were constructed as described by Haenszel et al. (1962)

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assuming a Poisson distribution. Payments for paid lost wages and impairment (together referred to as indemnity payments) and for medical care were used to calculate payment rates per $100 of payroll by type of work. To gain a better understanding of the circumstances surrounding slips and trips and to identify opportunities for prevention, we examined the distributions of the broad Haddon categories of contributing factors (victim, coworker, objects such as equipment or materials, environmental and organizational factors). We further reviewed and coded the text data for intrinsic victim-related factors that may have contributed to the slipping or tripping such as loss of balance, lightheadedness, fainting, etc., and to determine whether the worker was performing a task, carrying an object, or walking from one area to another when the injury occurred. Text analyses were facilitated by the generation of a series of text reports allowing us to examine contributing factors more closely. 3. Results 3.1. Injury characteristics and rates by mechanism of injury event Text data from FRIs and/or AIRs were available for 4148 of the 4634 injuries (89.5%) incurred at DIA. Of these, we could identify 751 (18.1%) injuries preceded by a slip or a trip. The injuries were almost evenly split between those that did and those that did not result from a fall (see frequencies and rates in Table 1). Overall, injuries that were preceded by slipping or tripping occurred at a rate of 5 (95% CI 4.6, 5.4) per 200,000 h worked. Rates varied by MOIE with injuries preceded by a slip/trip without a fall occurring at the highest rate, followed by those resulting in a same level fall and those resulting in a fall from elevation. Slips and trips preceded 58% of all falls on this construction project including 31.3% of falls from height ðn ¼ 290Þ and 85.6% of falls from the same level ðn ¼ 353Þ. In 532 instances (70.8%) the injured worker slipped and in 75 (23.3%) he or she tripped; in the remaining 44 (5.9%) the worker was described as losing balance. In Table 2 the nature of the slip/trip injuries sustained and the body parts injured are presented by the MOIE. The

Table 1 Frequency and rate of injuries sustained from slips/trips by mechanism of injury, building of Denver International Airport, 1989–1994 Mechanism of injury Slip/trip without fall Fall same level, started with slip/ trip Fall from elevation, started with slip/trip Total a

Injury rates are per 200,000 h.

Frequency (%) 378 (50.3) 302 (40.2) 71 (9.5) 751 (100.0)

Ratea (95% CI) 2.5 (2.2, 2.8) 2.0 (1.8, 2.2) 0.47 (0.37, 0.60) 5.0 (4.6, 5.4)

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vast majority of injuries were soft tissue injuries described as sprains, strains or contusions, followed at much lower percentages by fractures and lacerations. Injuries were most common to the lower extremity, followed by the upper extremity and the back. The distributions of nature and body parts injured varied significantly by MOIE. There were proportionately more sprain/strains resulting from slips without falls, more contusions from falls from the same level, and more fractures from slips that resulted in a fall from height. More injuries involving multiple body parts were the result of falls from height as expected. Slips without falls more often resulted in injuries to the lower extremity and less to the back and trunk than falls from the same level or from height. Slips and trips occurred across all construction domains although the vast majority occurred in building construction (Table 3). Work hours were not available for each domain making it impossible to calculate rates. Similarly, we did not have work hours available by age that would allow the calculation of age-specific rates. Because we had age for only the injured population, we could not compare the age of those who slipped with those who were not injured in any manner. However, the mean age of individuals who sustained a slip or trip injury was higher than that of individuals who sustained other injuries (38.8 years compared to 36.7 years; po0:001). 3.2. Injury and payment rates by type of work Injury and payment rates are presented in Table 4 by type of work. Injury rates varied from a low of 1.4/ 200,000 h worked in engineering and architecture to a high of 9.9/200,000 h worked in roofing; it is worth noting that these opposite ends of the spectrum are based on small numbers of events. Individuals performing carpentry, iron/ steel erection over two stories, and electrical wiring were injured at rates significantly higher than the overall group. Slips and trips were the source of over $10 million in workers’ compensation payments out of a total of $42 million for the DIA project, representing 24.8% of total payments. Payment rates for these injuries per $100 of payroll were quite variable ranging from a low of $0.04 in insulation work to a high of $20.56 in roofing, with an overall rate of $4.26. Seven high cost slips/trips (top 1%) accounted for 36% of payments. 3.3. Activities at the time of injury and contributing factors We were able to identify 358 (47.7%) cases in which the worker was performing a task and 156 (20.8%) cases in which he or she was transferring from one place to another on site when he or she slipped, tripped or lost balance; in 237 (31.6%) instances, information was insufficient to allow us to determine what the victim was doing. Transferring activities included walking as well as descending or ascending stairs in the structure or on-site buses, for example. When slips occurred while ascending or

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Table 2 Nature of injury and body parts injured by mechanism of slip/trip injury, building of Denver International Airport, 1989–1994 Frequency (%) Fall from height Nature of injury Sprain/strains Contusions Fractures Lacerations All others Total Body part Head/neck Back/trunk Upper extremity Lower extremity Internal injuries Multiple Eye Total

Fall same level

Slip without fall

Overall

27 (38.0) 20 (28.2) 12 (16.9) 4 (5.6) 8 (11.3)

124 (41.1) 106 (35.1) 28 (9.3) 19 (6.3) 25 (8.3)

269 (71.2) 48 (12.7) 14 (3.7) 24 (6.4) 23 (6.1)

420 (55.9) 174 (23.2) 54 (7.2) 47 (6.3) 56 (7.5)

71 (100.0)

302 (100.0)

378 (100.0)

751 (100.0)

4 ( 5.6) 19 (26.8) 15 (21.1) 19 (26.8) 2 ( 2.8) 12 (16.9) —

9 ( 3.0) 73 (24.2) 89 (29.5) 90 (29.8) 13 (4.3) 28 ( 9.3) —

71 (100.0)

302 (100.0)

3 (0.79) 49 (13.0) 56 (14.8) 251 (66.4) 11 (2.9) 7 (1.9) 1 (0.26) 378 (100.0)

16 (2.1) 141 (18.8) 160 (21.3) 360 (47.9) 26 (3.5) 47 (6.3) 1 (0.13) 751 (100.0)

Distribution of nature of injury and body part injured significantly different by mechanism of injury; Cochran Mantel Haenzel w2 ðpo0:01Þ.

Table 3 Construction domain where slips/trips occurred by mechanism of injury, building of Denver International Airport, 1989–1994 Domain

Frequency (%) Fall from height

Site development Roadway Airfield Building Utilities Administration All others Total

Fall same level

Slip without fall

Overall

9 (12.7) 4 (5.6) 9 (12.7) 40 (56.3) 6 (8.5) 1 (1.4) 2 (2.8)

13 (4.3) 10 (3.3) 28 (9.3) 216 (71.5) 12 (4.0) 18 (6.0) 5 (1.7)

17 (4.5) 14 (3.7) 46 (12.2) 250 (66.1) 30 (7.9) 8 (2.1) 13 (3.4)

39 (5.2) 28 (3.7) 83 (11.1) 506 (67.4) 48 (6.4) 27 (3.6) 20 (2.7)

71 (100.0)

302 (100.0)

378 (100.0)

751 (100.0)

descending heavy equipment, scaffolds or ladders these were considered to be part of performing a work task. In 86 (11.5%) instances the worker was described as carrying something at the time of the injury; in 21 of those 84 instances, or 24.4%, the object size or weight was felt to have contributed to the injury. Carrying was not related to whether the individual fell or slipped without falling (CMH, p ¼ 0:15). The factors identified in the text records as having contributed to these injuries are presented in Fig. 1. The contributing factors are not mutually exclusive. Although there was some variability by type of injury, environmental factors were mentioned more often than any others. The types of environmental factors recorded on injury reports are presented in Table 5. The condition of the walking surface contributed in half of the injuries, followed

by a step up or down, and slippery conditions involving work surfaces or outside terrain. Fig. 2 shows the rates of slip/trip injuries by month, ranging from a low of 3.5/200,000 h worked in October to a high of 6.6/200,000 h. Weather and slippery conditions (terrain and non-terrain) were twice as likely to be associated with slips in the winter months from November through March compared with the warmer, dryer months of April–October (prevalence ratios comparing contributions of weather, slippery terrain, and slippery non-terrain in winter vs non-winter months were 2.3, 2.6, and 2.5, respectively). Few human contributing factors were reported, the most common being inappropriate behavior; occasionally fatigue, safety infractions, or specific activities such as pushing or pulling were mentioned. Among the 44 injuries in which

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Table 4 Injury and payment ratesa by type of work; slips and trips, building of Denver International Airport, 1989–1994

Table 5 Environmental factors contributing to slips and trips as identified from text data, building of Denver International Airport, 1989–1994

Type of work

Frequency

Injury rate (95% CI)

Environmental condition

Frequency

Percent of slip/trip injuries with factor

Electrical wiring Concrete construction Street road/ construction Plumbing Carpentry Iron/steel42 stories Heavy equipment Superintendent Metal/steel installation Glass installation Conduit construction Clerical Pipefitting Inspectors Sheet metal Masonry Engineers/architech Roofing Elevator construction Insulation Overallb,c

128 109 109

6.7 (5.6, 8.0) 6.7 (5.4, 8.2) 4.2 (3.4, 5.1)

375 188 140

49.9 25.0 18.7

55 48 38 38 23 19 19 18 15 14 13 11 11 8 6 6 5 751

6.2 7.8 9.1 4.6 1.6 8.6 8.7 7.8 2.1 3.4 4.4 3.4 3.1 1.4 9.9 5.2 6.4 5.0

Walking surface Step-up down Non-terrain slippery surfacea Terrain Slipperyb Rough Hole Dirt clod Steep Rock Trench Other terrain Poor lighting/darkc Weather Loose concrete Tight work area All other

84 21 16 16 15 10 4 16 23 21 11 2 7

11.2 2.8 2.1 2.1 2.0 1.3 0.53 2.1 3.1 2.8 1.5 0.27 0.93

Payment rate

$0.98 $3.96 $4.79

(4.6, 8.2) (5.8, 10.3) (6.5, 12.4) (3.1, 6.6) (1.0, 2.4) (5.2, 13.4) (5.2, 13.5) (4.6, 12.3) (1.4, 3.0) (1.9, 5.7) (2.3, 7.5) (1.7, 6.1) (1.5, 5.5) (0.60, 2.8) (3.6, 21.5) (1.9, 11.3) (2.1, 14.9) (4.6, 5.4)

$0.90 $2.30 $2.80 $0.64 $0.71 $2.52 $13.20 $2.36 $1.10 $0.30 $1.55 $0.72 $0.47 $0.02 $20.56 $1.26 $0.04 $4.26

Note: Factors are not mutually exclusive. a Includes variety of working surfaces such as floors, steps, truck bed. b Slippery terrain was not assigned to weather code; mud for example. c Poor lighting was assigned as an environmental condition, as opposed to an organizational factor, to injuries that occurred outside.

a

Injury rates are per 200,000 h; payment rates are per $100 of payroll. Only types of work with 45 slip/trip injuries. No slips/trips were identified in boiler making, plastering/finishing, stone crushing, pile driving, driving, crane hoisting, iron/steel erection under 2 stories, electrical power line work, concrete/bridges, painting, or low voltage specialties. c Remaining slips in ‘other’ category are not reported here. b

Falls from height

Same level falls

Slip/trip wo fall

60

Percentage of contributing factors identified

50 40 30 20 10

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the worker was described as having lost his/her balance, in only three cases was there any reference in the text to intrinsic factors that may have contributed to the injury. These included a likely orthostatic episode in which a welder who stood up from working lost his balance, dizziness with reference to heat, and an episode of chest pain. The other ‘losses of balance’ were similar to other slip injuries and involved a variety of activities including lifting, using a prybar, pushing or pulling, stacking materials, operating equipment, stepping wrong, over-reaching laterally, reaching below feet for materials, descending a ladder, catching clothes on heavy equipment while descending, and walking across beams or concrete forms. Organizational factors were most often related to inadequate housekeeping. There were occasional references to the contribution of proximity of a co-worker, staging, equipment or tools provided, and unfinished work. Poor housekeeping was, at times, related to debris left from an earlier crew—possibly other trades; at other times it was clear that the worker slipped on debris he/she had recently created. Housekeeping and weather jointly contributed to one of the very high cost claims when a worker fell, after slipping on a piece of plastic covered by snow.

Fig. 1. Factors identified in text records as contributing to injuries preceded by slips/trips by mechanism of injury, building of Denver International Airport. Note: Factors are not mutually exclusive. Equipment and tools includes ladders, scaffolds. Environmental includes trenches, dirt clods, and dust, as well as snow, ice, mud and weather.

4. Discussion Slips and trips accounted for 18% of all injuries sustained in the building of the DIA and 25% of workers’ compensation payments. The injuries occurred across most types of construction work, but we found different levels of

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Fig. 2. Rates and 95% confidence intervals (injury rates are per 200,000 h) for slip/trip injuries by month, building of Denver International Airport, 1989–1994.

injury risk and severity for different types of work. The distribution of payments associated with these injuries was highly skewed, as is often the case with insurance claims, with the top 1% of claims responsible for over a third of all payments. The text descriptions of the high cost injuries were very similar to less costly events, making it difficult to tailor prevention recommendations to the more catastrophic events. But the fact that there were catastrophic slip/trip injuries makes prevention of all of them important. In contrast to patterns seen for some other types of injuries on this project in which victim related factors were more common (Glazner et al., 2005), environmental factors were by far the most frequent contributors to slip/trip injuries. These included the condition of walking and working surfaces, steps, terrain, uneven surfaces, lighting, and weather. Construction materials, cords, hoses, wet surfaces, dust and debris also contributed to injuries. In 20% of injuries, the victim was not performing a work task but transferring from one place to another on site, on foot or on site buses or vehicles, when the slip or trip occurred. This points out the importance of preventive efforts addressing safe walking areas and vehicle transfers on a large construction site such as this one. The findings reported here are consistent with reports of others in several aspects. Environmental risk factors on this construction project included damaged surfaces, steps and rails, grades, and weather as reported by others (Bell et al., 2000; Bentley and Haslam, 2001). Those who sustained an injury as a result of a slip or trip were older than other injured workers, which is consistent with reports of increased risk of slipping injuries with aging (Davies et al., 2001; Kemmlert and Lundholm, 2001). The 2-year mean age difference in this relatively young group of workers may not, however, be meaningful. Although slips or trips contributed to a slightly greater proportion of falls on this construction project (58%) than was reported by Courtney et al. (2001b), we similarly found slips or trips to be more often a factor in falls from the same level than in falls from height. One possible

explanation for the different findings is that Courtney’s estimate that 40–50% of fall-related injuries related to slips or trips was not limited to any particular industry. In addition, our findings document a significant contribution of slips to musculoskeletal injuries that occurred when the worker slipped or tripped but did not fall, and these were among the most costly injuries. These analyses did not include falls that were not preceded by a slip or trip. In our previously reported analysis of all falls from elevations (Lipscomb et al., 2004) on this large construction project, approximately one-third (31.3%) were preceded by a slip or a trip. The remaining falls from height were related to other circumstances such as collapse of work surface and falls through openings for which the contributing factors were quite different. Failing to recognize the contribution of slips and trips to falls from height underestimates the injury and financial burden for which they are responsible, while grouping all falls together in analyses exploring risk is a form of misclassification that will likely result in inaccurate findings. 4.1. Limitations and strengths These retrospective analyses are based on existing data from one large construction project. As with any analyses based on workers’ compensation records anything which influences the reporting of injuries will be reflected in the data available for analyses. The injury reports and accident investigations that we used for text analyses were collected by safety personnel at the time of injury. The text of these reports varied in quality and detail and was often limited to only a few lines of information. As would be expected, some of the more serious events had more detailed accident investigations. Unlike text systems such as MAIM (Davies et al., 2001) where a standardized guided interview allows collection of more complete information, these data do not lend themselves to hypothesis testing. Despite the fact that organizational factors were rarely noted, it is certainly possible that they played a more

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significant role than we have reported. Organizational factors accounted for only 4% of factors identified in injury reports as contributing to all 4148 injuries. Injured workers were quick to blame themselves reporting they ‘‘should have been more careful,’’ demonstrating some acceptance of conditions contributing to these injuries as the norm. Managers have been reported to have different perspectives on causes of slips/trips than do workers (Lehane and Stubbs, 2001); safety personnel and workers may be more apt to focus on the immediate situation, giving less attention to safety culture. For example, it is reasonable to assume that the condition of walkways and work surfaces could sometimes have been remedied by organizational housekeeping policies even though these policies were rarely explicitly noted in injury reports. We might have found different results if a structured protocol that explicitly considered organizational contributions was used to investigate all injuries. Despite these limitations, the combination of administrative and injury report data allowed us to perform several useful analyses. Workers’ compensation data typically lack information about the population at risk of injury. Using the administrative data on hours worked that were available in aggregate from contractors’ payroll data, we were able to estimate work hours by type of work. This allowed calculation of injury and payment rates that can be useful in targeting prevention activities to high-risk types of work. We also believe that recognizing the underlying costs of slips and trips is important in justifying expenditures for prevention; these injuries alone accounted for over $4.00 for every hundred dollars of payroll. These data add to the work of Courtney et al. (2002) documenting the burden of injuries in construction secondary to slips and trips. The limited text data showed that the pattern of factors contributing to slips and trips is different from that for other types of injuries on this project; victim-related factors accounted for over half of the contributing factors overall but less than 10% in slip/trip injuries, for example (Glazner et al., 2005). A number of strategies have been suggested to prevent slips and trips, including frequent and regular housekeeping, walk-through assessments to identify hazards or contaminants, and consistent use of slip resistant surfaces and shoes (Bentley and Haslam, 2001; DiPilla, 2001; Kemmlert and Lundholm, 2001; Leamon, 1992). In the constantly changing construction work environment, policies that dictate frequent surveillance of hazards and housekeeping could make significant contributions in preventing slips/trips in building erection, but they may not adequately address issues in site development and roadway construction. In these domains, attention must focus on prevention of slips related to heavy equipment and vehicles as well as terrain and weather. Many injuries occurred while the worker was walking on the site. This finding suggests the need for ensuring that proper indoor and outdoor walkways are kept clear of debris and adequately maintained as weather changes; this will require

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policies that do more than require workers to clean up their own work areas. Construction involves significant manual materials handling which could contribute to slips and trips by changing the center of gravity and altering the balance of the worker, obstructing view, or preventing use of handrails on steps. Engineering solutions that improve methods of manual materials handling, or minimize these activities, could decrease slips/trips as well as injuries resulting from lifting and carrying. These findings point to a need for additional research focused on the prevention of these injuries from the perspectives of engineering, human factors and construction management. Construction work boots are designed to provide foot protection and traction. Designs that take into account the surfaces workers are likely to be exposed to and how work contaminants may alter the coefficient of friction and tread life in this environment could be useful. Temporary surfaces are available to protect floors and to prevent slipping. The type and longevity of temporary surfaces may vary by the type of contaminants occurring on site, e.g. dusts, oily or wet substances, and even soil type. Different coverings may be appropriate in different seasonal conditions or climates, and understanding these differences could positively affect costs as well as safety.

5. Conclusions/recommendations Slips and trips are a serious source of injury in construction. Non-fall slips and trips resulted in a significant number of musculoskeletal injuries, and these injuries were, somewhat surprisingly, among the highest cost injuries. The fact that a significant number of slips contributed to falls from height points to a continued need to address fall prevention and protection when working at heights, even while ameliorating slip/trip hazards (Lipscomb et al., 2003, 2004; Kisner and Fosbroke 1994). The burden of these musculoskeletal injuries and falls from height that were initiated by a slip or trip would have been under-recognized in analyses of most coded workers’ compensation records. The fact that human factors were rarely identified as contributing to slip/trip injuries suggests that prevention efforts concerning slips and trips in construction are unlikely to be successful if they are directed solely at the behavior of individual workers. The complexity of the factors we found to contribute to slip/trip injuries suggests that there is some interplay among environmental, behavioral and organizational factors that requires a broad framework for analyzing injury etiology and for developing interventions. Prevention of these injuries may require engineering analysis of the equipment, materials and materials handling, and site characteristics contributing to slips and trips. Policy changes at the organizational level may also help to reduce slip/trip hazards. In any case, the nature of construction calls for dynamic preventive actions that take into account equally dynamic site characteristics.

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