Melvin L. Myers, MPA Photo courtesy North Carolina Department of Labor. Acknowledgments Nancy Calkins, Data Analyst, Caldwell, Idaho, was helpful in compiling data from the OSHA Web site used in this analysis. Resources from the Hazard Information Foundation, Inc., Sierra Vista, Arizona, assisted in identifying and describing some of the cases that were analyzed. In addition, Cok, Wheat, Brown, McGarry & Bidegaray, PLLP, Bozeman, Montana, provided discovery materials useful in designing the approach to this study. The North Carolina Department of Labor provided photographs used in this report's cover and elsewhere. The U.S. Department of Energy also provided one photograph used in this report. Many federal OSHA offices provided copies of their inspection reports for this study. They include the following area offices: Albany, Atlanta East, Atlanta West, Austin, Avenel, Baton Rouge, Billings, Birmingham, Buffalo, Calumet City, Chicago North, Cincinnati, Cleveland, Columbus, Corpus Christi, Dallas, Erie, Fort Worth, Houston North, Houston South, Indianapolis, Jackson (Miss.), Little Rock, Lubbock, Madison (Wisc.), Manhattan, Oklahoma City, Peoria, Philadelphia, Phoenix, Denver, Portland (Ore.) , Syracuse, Toledo, Utica, and Wilkes-Barre. In addition, the following state programs provided copies of their investigation reports: Alaska, California, Indiana, Kentucky, Maryland, Minnesota, New York, North Carolina, Oregon, South Carolina, and Washington. Abbreviations
Contents
Army Corps of Engineers Requirements Other Governmental Actions ROPS Effectiveness and Availability Types of Compactors Machine, Environmental, and Human Factors
Environmental Factors Human Factors Seatbelt Effectiveness OSHA Enforcement Discussion and Recommendations References Tables Annexes Compactors - also known as steamrollers - are mobile vehicles used to increase the density of soil and roadways and to seal and smooth asphalt surfaces. Compactors tend to overturn during some operations, thus putting their operators at risk. A rollover protective structure (ROPS) is a part of a compactor or other heavy equipment designed to protect an operator from a crushing injury in the event of a rollover. Particularly with seatbelt use, ROPSs have been shown to save lives. In 1971, the Employment Standards Administration, part of the U.S. Department of Labor, drafted the following language under the Construction Safety Act: "The promulgation of specific standards for rollover protective structures for compactors...is reserved pending consideration of standards currently being developed." The newly established U.S. Occupational Safety and Health Administration (OSHA) adopted the language in its rules the following year. Although consensus standards were developed soon thereafter (by the Society of Automotive Engineers), the OSHA rules were never changed to require ROPS on compactors. This study examined government investigation reports of work-related deaths and injuries in 1986- 2002 to learn the public health implications of a widespread lack of ROPS and seatbelts on compactors. Among the findings:
Although ROPSs likely would save lives and prevent serious injuries of compactor operators, particularly with seatbelt use, the U.S. Occupational Safety and Health Administration (OSHA) has not promulgated a standard that would require the devices - and seatbelts - on compactors. The expectation for such a standard was based on a 1972 construction-equipment ROPS standard, which excluded compactors yet stated:
Several questions drove the analysis. First, was a suggestion by Brickman and Barnett (1999) that ROPS present more of a hazard in an overturn than if they are not installed. Another is the question of the general effectiveness of ROPSs for compactors. A third issue has been the added value of seatbelt use. Fourth, what have been OSHA and industry responses thus far to the problem. Decades ago, studies identified unstable embankment foundations as unable to support the weight of a compactor (Ritter and Paquette 1960, p. 374) and operating compactors at the edge of high fills as dangerous (Baker 1957). The Naval Training Command wrote that a "roller is easier to overturn than most other equipment," adding that rolling a shoulder presents a risk of an overturn into a ditch (1973, p. 375). Some early statistics indicated a pernicious problem related to compactor overturns. California reported 14 compactor overturn-related deaths between 1965 and 1972 (White 1973). Woodward Associates' 1974 analysis reported 13 compactor overturn-related injuries during 1971 and 1972 in California. The Construction Industry Manufacturers Association, CIMA, alerted the public to the hazard of operating compactors on slopes in a booklet (1978): "the danger of sliding and/or tipping on steep slopes is always present regardless of how heavy or stable your machine may appear to be." The booklet identified the potential of caving edges also. CIMA recommended always wearing a seatbelt on a compactor that was equipped with an ROPS; avoiding operating a machine too close to an overhang, deep ditch, or hole; and always traveling slowly over rough terrain and hillsides. Between 1950 and 1970, two ROPS standards emerged that affected construction equipment: a Society of Automotive Engineers recommended practice and U.S. Army Corps of Engineers design criteria. Besides the Army Corps move, several government entities established ROPS standards: the states of California and Oregon, and the U.S. Departments of Agriculture (Forest Service) and Interior. In addition, several state highway departments specified ROPSs in purchase orders for construction and highway maintenance equipment. The Society of Automotive Engineers Recommended Practice In 1966, the Society of Automotive Engineers (SAE) began developing recommended practices for protective devices for mobile construction and earthmoving equipment. The SAE developed a standard to allow an ROPS to yield through deformation and absorb some of the energy of a rollover so as to lessen the violence of the overturn. The structure was designed to deform through a plastic range that would neither break nor intrude into the operator's protective zone (National Safety Council 1976). It was not until 1975, however, that the SAE issued a recommended practice for ROPSs on compactors, classifying them as earthmoving construction equipment. In 1981, the SAE reclassified compactors as other than earthmoving machines (SAE 1975, 1981), thus removing compactors from a classification that included bulldozers, scrapers, and graders. Army Corps of Engineers Requirements The Corps of Engineers began requiring heavy canopies as rollover protection on crawler tractors in 1960. In 1967, the Corps issued its Safety-General Requirements, which required steel canopies and seatbelts on any construction equipment that presented a construction hazard, including compactors (Article 18.A.20). The manual required a canopy design that would support twice the weight of the machine and provide at least a 52-inch clearance from the machine's deck to the roof of the canopy. Other Governmental Actions Pursuant to the Construction Safety Act of 1969, the U.S. Department of Labor announced a notice of proposed rulemaking in 1971 to add Safety and Health Regulations for Construction to the Code of Federal Regulations (Federal Register, Feb. 2, 36:22). The proposed regulations included compactors as earthmoving equipment and required ROPSs to conform to SAE minimumperformance criteria. The final rule, published in 1971, read, "The promulgation of specific rules for compactors and rubber-tired "skid steer" equipment is reserved pending standards currently being developed." (Federal Register, April 17, 36:75) With the passage of the Occupational Safety and Health Act (OSHAct), which took effect on April 29, 1971, publication of the construction rules in the Code of Federal Regulations was delayed until 1972, when OSHA published a rule for ROPSs that exempted compactors, as well (Federal Register, 37:66, April 5). In 1972, however, OSHA notified the public that if a standard was reserved with a delayed effective date, the working conditions would be subject to the General Duty Clause, Section 5(a)(1) of the Occupational Safety and Health Act. Under this clause, OSHA may cite an employer for failing to provide a place of employment free from recognized hazards that are likely to cause death or serious physical harm. OSHA named the lack of an ROPS as such a hazard in certain situations, but also named other factors, such as machine speed, nature of the soil, the grade of the terrain, falling-object risk, and training. In 1976, California issued safety regulations that required ROPSs and seatbelts on rollers and compactors (Division of Industrial Safety 1976). The Office of Management and Budget issued its Regulatory Program of the U.S. Government for April 1, 1985 to March 31, 1986. In the document, OSHA stated its intention to amend the current ROPS standard so as to eliminate gaps in coverage and specifically named the problem of deaths associated with compactors. OSHA stated that the installation of ROPSs and seatbelts on compactors could have prevented deaths, but said seatbelts were not required in 1971 because of the unavailability of technology (OMB 1985) (see below). In the meantime, Miles (1986), of the OSHA Directorate of Field Operations, specified that the General Duty Clause could be cited when compactors were used in a manner that posed a recognized hazard to the operator. In preparation for the ROPS rule, OSHA established a task force to develop requirements for compactors (Richter 1987). The task force recommended that compactors be equipped with ROPSs, as specified in SAE Recommended Practice J1040 (1986); that ROPS be designed to support at least two times the weight applied at the point of impact; and seat belts meet SAE J386. The industry expected OSHA to require ROPSs on all compactors in late 1988, and at least one company planned to offer ROPSs on all of its compaction equipment as standard equipment (Richter 1987). OSHA never promulgated the rule. ROPS Effectiveness and Availability Protective canopies for crawler tractors and anti-roll bars for agricultural tractors had emerged in the 1950s (Myers 2000). The first patent for an agricultural tractor protective frame was issued in 1954, and the first use of an anti-roll bar on roadside mowing tractors was in 1958 (Skromme 1986). Construction equipment canopies were available from several manufacturers in 1958 (MacCollum 1958). Protective structures were demonstrated to be effective as early as 1956 by the U.S. Forest Service in overturn tests conducted on crawler tractors (E&R 1956). Anti-roll bars on mowing tractors were designed to prevent a roll beyond 90°, which proved to significantly reduce deaths from this type of work. These tractors experience slope exposures similar to the edge work of compactors. Starting in June 1973, Woodward Associates (1974) conducted a study for OSHA on the feasibility of retrofitting ROPSs on construction equipment, excluding compactors. Nonetheless, fatality data analyzed from California and the Corps of Engineers included compactors. The study concluded that ROPSs clearly reduced injuries and deaths related to vehicle rollovers. Moreover, the study found that ROPS designs were available for most heavy-construction equipment manufactured after 1960 and that rollovers occurred in all types of terrain and to all types of vehicles.
Source: Woodward Associates 1976. Types of Compactors In 1973, the Society of Automotive Engineers described three types of compactors: tamping (pad) foot compactors, smooth steel rollers, and rubber-tired rollers in a nomenclature standard. The standard referred to compactors (also called "rollers") as smooth-drum, pad-foot (sometimes called "sheepsfoot"), and rubber-tired (also called "pneumatic") (figs. 1-3). Both the smooth-drum and padfoot compactors were manufactured as double drum or single drum, and some had a vibration mechanism designed into the drum wheels to assist in compaction. Units lacking the vibration feature were called static compactors. On compactors, an ROPS can be designed with two posts or four posts (fig. 4) and can have a canopy overhead to provide shade; these canopies may be designed as part of the ROPS system. Some modern compactors use a single-post ROPS with a canopy extending to the sides to absorb the impact of an overturn. A principle in ROPS design is to restrict an overturn to no more than 90°. The collection of cases to be analyzed followed a two-step process. First, the researcher identified OSHA inspection reports and Fatality Assessment and Control Evaluation (FACE) investigations of compactor overturns and runovers by the National Institute for Occupational Safety and Health (NIOSH). Four of OSHA reports were also included in the NIOSH investigations. Most of the cases were found on the internet at the OSHA and NIOSH websites. Others were identified from newspaper articles, litigation files, and through assistance from the Portland, Oregon, Area OSHA Office. A total of 123 cases was identified. The next step was to request the complete investigation report from OSHA under the Freedom-of- Information Act (although, to protect privacy, all names were expunged from the reports, except for decedents and officials representing the employers). The NIOSH reports were accessible through the internet. Case files were compiled for 58 injury events involving compactor overturns (table 2). The cases ranged from the year 1985 to 2002. Some OSHA reports related to the same incident; some addressed falls and collisions, as well as overturns. Eight others dealt with scheduled inspections in which the OSHA General Duty Clause was used to cite the lack of an ROPS or of a functioning seatbelt. OSHA data were not comprehensive and omitted many nonfatal events and all pre-1985 overturns, as well as incidents involving public employees where OSHA lacked jurisdiction. Data from the reports were placed into a Haddon matrix to analyze the role of machine, environmental, and human factors and the temporal dimension (before, during, and after) of each incident (Runyan 1998; Hadden 1970, 1980). In addition, flowcharts were used to understand the factors that comprised the causal chain leading to and the characteristics of each overturn (Feyer and Williamson 1998; Myers 1992). The Haddon matrix provided a way to categorize risk factors against three stages of an incident (see table 3). The first stage is pre-event (for example, compacting along an embankment edge); the second stage is the event (such as, an overturn); and the third stage is post-event (for instance, extrication). The risk factors were classified as related to the energy agent (such as, the compactor); the environment (for instance, a steep slope); and operator/driver (for instance, wearing a seatbelt).Nonetheless, because of limitations in the data, this analysis can't show whether one type of compactor is more dangerous than the others; there is no way to know how much of the work was done using each type. Table 2. 58 compactor overturn cases analyzed, with associated characteristics
NOTE: for NIOSH FACE reports see http://www.cdc.gov/niosh/injury/traumaconstructface.html
Machine, Environmental, and Human Factors Machine, environmental, and human factors contributed to the 58 compactor overturn injuries described in the OSHA and FACE investigation reports analyzed in detail (see table 2). Machine-Related Factors Of the 58 overturns, nearly half (27) related to the smooth-drum, with the remainder roughly divided between the pad-footed (15) and rubber-tired (13) compactors (fig. 5). The type of compactor in one case was unknown. For the pad-footed compactor overturns, all but two occurred along a road or embankment edge. One other overturn was initiated by an obstruction and another by sinking soft soil. The circumstances related to one overturn were unknown. Eight of the rubber-tired compactor overturns occurred at a road or embankment edge, and another five occurred when a unit went out of control as a runaway because of either brake or gear-shifting defects. As for the smooth-drum compactor, 20 of the 27 overturns occurred along roadway or embankment edges, four were runaways, one was cornering too fast, one was initiated by sinking soft soil, and the cause of one was unknown. In two cases, leaving a compactor vibrator engaged while stationary may have led to the settling of soil on one side of the unit, allowing it to drop at an angle and overturn. Research has also identified cases where articulation of a mobile unit with the jackknife pointed toward an edge presented a substantial overturn hazard. Three situations led to a hazard in articulated (prime mover and trailer) units. In one situation, the center of gravity of the prime mover and the trailer may have combined in the turned situation to lower the tip angle of the compactor. (In a turned position, the wheels are directed away from the center and may no longer support that portion of the vehicle.) In another situation, the unit's momentum may have aided a tripping situation for an overturn. In the third situation, when turning away from an edge, one set of wheels or drums pointed away from the edge while the other set pointed and moved toward the edge. A sloshing effect can also be a factor in overturns. Water may be used as ballast in ballast bins or in drums, and water tanks are typically mounted on compactors as a source for spraying. This water or other liquid can slosh toward a slope causing a shift in the center of gravity of the unit. In another case, an operator steered across a road, but the steering angle of the machine did not allow him to turn sharply enough to become parallel with the edge, and thus, he went over the edge. More than half - 55% - of the compactors involved in the 58 overturns did not have ROPSs, including 93% of the rubber-tired ones. The lack of an ROPS was a risk factor for an injury. By contrast, an ROPS in combination with a seatbelt offered a system of operator protection in the case
of an overturn. However, two new compactors failed to have a seatbelt installed, and two other
seatbelts were inoperable with a broken latch and a missing nut needed to secure the belt to the unit.
Environmental Factors The most significant environmental factor contributing to compactor overturns was found to be working near an edge of a road or embankment (see fig. 5). The slope at which an overturn was initiated ranged from 12° to 45°, and some overturns occurred with abrupt drop-offs such as over a pavement edge. A compactor may extend over an edge, an edge may give way and sink, or an edge may be sloped so that other factors may accumulate so as to reach the tip angle of the unit. There were two cases in which a compactor sank on a deep asphalt pour that was still warm and caused a tipping situation. Next in significance in this category were steep slopes and roadway curves, where gear-shifting problems or poor brakes led to runaways (fig. 7). Indeed, steep slopes and curves at the bottom of a roadway have combined to present an overturn hazard; notably, no pad-footed compactor experienced a runaway, perhaps because that type of compactor does not operate on smooth surfaces. Other conditions contributing to runaways included hitting soft soil areas that depress on relatively level land, turning too fast, and kinetic issues such as striking rocks or other obstructions in a roadway. In connection with the environment, the type of operation was also associated with compactor overturns. In compacting soil, pad-footed and smooth-drum compactors predominate, because rubber-tired compactors are rarely used for this task. Driving a compactor from one location to another as a method of transport was also related to overturns, principally through runaway excursions. Compacting roadway shoulders presented a risk because a shoulder is an edge. When a compactor attempted to stay off asphalt while compacting a shoulder, some overturns occurred where a shoulder wasn't wide enough. Asphalt compacting presented a risk at the road edge where the deep, hot mix sank under the compactor's weight and on slopes when runaway excursions occurred on the smooth surface. Hazards during gravel compacting may be similar to those associated with shoulder work Loading and unloading compactors from trailers posed hazards because of the lack of friction of a steel-drum on ramps, the sometime lack of adequate width to reach from one ramp to another, the occasional use of unstable boards as ramps, or unloading onto a slope where a runaway was possible after descending a ramp. Compacting stone may be hazardous because the stone can be slippery. Landfills present irregular and steep terrain. Human Factors The most serious human factor was a lack of seatbelt use, or an operator's unbuckling a seatbelt during an overturn and attempting to jump. However, using seatbelts without an ROPS is a recognized crushing hazard also, and one individual was belted in while there was no ROPS. In an overturn without an ROPS, the operator's chance of survival depends on jumping clear of the overturn path. One victim was unable to jump because of a disability. Possible ROPS Design Defects compactor. Several cases included runaway units that did not overturn, but from which operators fell or jumped and were injured by the impact of the fall. An ROPS-seatbelt combination might have prevented injuries, if a seatbelt had been used. Other situations involved collisions with either offhighway or highway vehicles in which a seatbelt likely would have saved lives. The victims in the two collisions that did not involve overturns were thrown off a compactor by the force of a collision and killed by the impact of the crash. Until the early 1990s, OSHA typically excluded overturns from ROPS-related citations, because a standard was not in force. However, some jurisdictions and states used OSHA's General Duty Clause to cite employers who failed to provide a workplace free of the overturn hazard. In addition, compliance officers used the clause to cite employers for not requiring the use of a seatbelt in the presence of an ROPS. The OSHA 1998 directive (Swanson) provides for consistency in citing the lack of an ROPS as a violation under the clause. Six compactor-overturn cases were cited as General Duty Clause violations between 1999 and 2002. Workers continue to die and suffer injury from overturns of compactors lacking ROPSs more than 30 years after the passage of the Occupational Safety and Health Act of 1970, which established OSHA. The problem has long been recognized. As long ago as 1974, in his report to OSHA, Woodward felt compelled to offer insight - albeit unsolicited - into a myth of compactor safety:
Several recommendations are offered as a result of this study.
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Figure 5. Number of compactor overturns resulting in operator
injury, by conditions and type of compactor, 1985-2002 Annex B: The Usefulness of OSHA and NIOSH Reports for This Research |