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Text from the OSHA Logging Preamble Text from the OSHA Logging Preamble

Section IV: Major Issues

A. Introduction

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6. Chain-saw protective devices. In the proposed standard, OSHA did not include a provision requiring chain saws to be equipped with chain brakes or other devices that prevent kickback. The proposed standard also did not require chain saws to meet any performance criteria of any standards-setting organizations. Rather, OSHA proposed only to require employers to inspect and maintain chain-saw safety devices when chain saws were so equipped. The hearing notice requested further comment on the adequacy of various chain-saw safety devices and what regulatory action OSHA should take in the final standard regarding chain saws.

There was no dispute among commenters that chain-saw protective devices are necessary to prevent operators from being injured. The record shows that the chain-saw bar can kick back in less than 0.3 seconds (Ex. 4-172). The record also shows that average human reaction time, however, is only 0.75 seconds (Ex. 4-172). That means in many cases the operator cannot take action quickly enough to avoid being struck by the chain saw. The record also shows that many injuries in the logging industry are the result of chain-saw kickback. According to the WIR survey, 20 percent of all logging injuries reported involved chain saws and almost two-thirds of those injuries were the result of chain-saw kickback (Ex. 2-1). The Maine BLS survey also shows that chain-saw injuries account for a significant number of logging injuries (26%) in that State (Ex. 4-175). Similar to the WIR survey, the Maine BLS survey indicated that over half of all chain-saw accidents resulted from kickback.

a. Devices to prevent chain-saw kickback. Information submitted to the docket indicates that there are four devices that exist to reduce or minimize the risk of injury due to chain-saw kickback. These devices are chain brakes, bar tip guards, reduced-kickback guide bars, and low- or reduced-kickback saw chains. Information about these devices was taken from a 1983 report prepared for the Consumer Product Safety Commission (CPSC) (Ex. 5-13) as well as comments to the proposed rule. The discussion that follows explains the different devices and their advantages and disadvantages.

The "chain brake" is a device for stopping the saw chain when kickback occurs before the chain can contact the operator. The most common type of chain brake is actuated when the operator's hand or arm hits the brake lever that is located immediately ahead of the front handle. When kickback occurs, the chain brake may either be actuated by the operator's hand pivoting forward on the handle, or by the hand being dislodged from the handle, striking the brake lever. According to the CPSC report, chain brakes, unlike new technology chains and safety guide bars, do not have any adverse effect on the cutting effectiveness of chain saws. The record also indicates that one of the advantages of chain brakes is that, unlike other protective devices that can be removed, the chain brake is an integral part of the saw and is difficult to remove (Ex. 4-174). As such, chain brakes deter the disabling of the kickback prevention system by the operator (Ex. 5-19).

The "bar tip guard" (or nose tip guard) is a device that is bolted or screwed onto the tip of the bar. Its primary function is to prevent contact with the tip of the bar from which kickback is generated. Commenters identified three problems with bar tip guards. First, one commenter said bar tip guards are not usable in felling and bucking of some trees (Ex. 9-16). This commenter said forward leaning trees usually require the bar tip to fell the tree safely.

Second, two commenters said the hazards associated with bar tip guards outweigh their protective value (Ex. 5-42, 9-20). According to NIOSH bar tip guards reduce kickback danger only under certain conditions, that is, when the log or limb is elevated and does not have any off-angle to cause pinching of the bar (Ex. 5-42). NIOSH concluded that the bar tip guard may pose greater hazards than saws without tips because they require the bucker to maintain working stances that are less stable. The other commenter said that the bar tip can get caught on limbs. Third, the major problem with bar tip guards is that they are removable (Ex. 5-13, 5-13H). According to the CPSC report, the bar tip guard is removed by operators because it reduces the utility of the saw by preventing boring and the cutting of any logs that are wider than the guide bar. Evidence in the record indicates that bar tip guards are being removed by a significant number of operators:

Only about half of the operators of saws so equipped always use such guards. About 36 percent never use them, and about 12 percent sometimes take them off the guide bar. Thus, while nose tip guards are effective anti-kickback devices, many operators remove them from their saws (Ex. 5-13).

The Portable Power Equipment Manufacturers Association (PPEMA) submitted testimony from CPSC's own proceedings, which also acknowledged the extent to which bar tip guards are removed from chain saws:

[T]he Commission received the benefit of a survey that was done on the part of the NESDA, National Equipment Servicing Dealers Association. They on their own surveyed hundreds of their dealers.

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[T]heir survey corroborated my own personal observations, namely, that in real life practice users of chain saws in the droves are simply not using that nose tip, and while if it were used or if it were permanently established on the saw, it would be a complete barrier to kickback, the fact of the matter is because it's temporary and because it is removed, because in my view it affects in the case of the dealers, as you'll see from their comments, it affects the efficacy of the saw, it is taken off, and as a result provides no protection, zero.

Just to cite from the survey, 73.5 percent of the responding dealers to the NESDA survey reported that only zero to five percent of the chain saws brought into their shops for repair, of the ones that were originally equipped with the nose guards, that 73.5 percent of the dealers responded that only zero to five percent had nose guards in place. Another 9.3 percent reported that six to ten percent of such saws had nose guards in place, leaving only 17.1 percent of the dealers who put the figure of nose guards in place at something more than ten percent.

The unmistakable conclusion is that the overwhelming majority of consumers are removing the nose guards from their saws and not putting them on in the first place.

The survey also revealed that almost no consumers are interested in replacing nose guards that are not in place. Eighty-eight percent of the dealers, 88 percent, stated that zero percent of their customers wanted replacements, and an additional 8.9 percent put the replacement request at a mere one to five percent (Ex. 5-13H).

There are two different types of "reduced-kickback guide bars". One is designed and manufactured with a taper from the back of the bar and has a correspondingly small radius of curvature at the tip of the bar. This type of bar is commonly referred to as a narrow nose bar. The other type of reduced kickback guide bar has a reduced radius nose but achieves its taper from the fact that the top and bottom edges of the bar a asymmetrical (the top and bottom edges are curved and have a different radius of curvature). This type bar is commonly called a banana bar because of its peculiar shape. According to the CPSC report, both the narrow nose bar and the banana bar have significant drawbacks, primarily in the useful life of the bar and chain and the efficiency of the chain saw. The narrow nose bar, because of its reduced radius of curvature at the tip, receives more stress at the tip, thereby requiring more frequent replacement. Because of its asymmetrical design, the banana bar cannot be merely turned over when the bottom edge of the bar becomes worn, but must be replaced. This type of bar also reduces the ability of the operator to use the saw for boring. This disadvantage is compounded if the saw also is equipped with a low- or reduced-kickback chain.

[T]he use of low-kickback guide bars results in a tradeoff of some reduction in utility for an improvement in safety. Industry sources have suggested that this may be an acceptable tradeoff for the less powerful saws which are probably purchased by consumers. Since the tradeoff involves a marginal improvement in safety, however, manufacturers are probably less willing to equip the more powerful, more performance oriented saws with the low-kickback guide bars (Ex. 5-13).

Finally, the potential for kickback can be reduced by the "low- or reduced-kickback chain". This chain is commonly referred to as new generation chain. Low kickback chain can be identified by an idler or spacer link between each of the cutting links. In other words, the chain has a left hand cutter link on the right side of the chain, followed by a spacer link, followed by a right hand cutter link on the left side of the chain followed by another spacer link before the sequence begins again.

Although the low-kickback chain can reduce kickback energy by 40 to 90 percent, there are drawbacks to its use, according to the CPSC report. These drawbacks include: (1) New technology chains generally exhibit some loss in cutting efficiency (speed and ease of cutting), (2) these chains make cutting more tiring for the operator thereby causing more operator fatigue, and (3) the loss of cutting efficiency may adversely affect the life of the chain. The loss of cutting efficiency has been estimated to be anywhere from a 10 to 25 percent. OSHA has no estimates of the increase in operator fatigue and the degradation in the service life of the chain.

Of the four protective devices, most commenters said OSHA should require chain saws to be equipped with a chain brake because it is the most used and most effective for professional logging operations (Ex. 4-175, 5-17, 5-19, 5-21, 5-27, 5-34, 5-42, 5-46, 9-3, 9-4, 9-13, 9-15, 9-18, 9-20; Tr. OR 536-37). Several of these commenters said that all chain saws used at their establishments are equipped with chain brakes. These commenters also said that almost all manufacturers now produce chain saws with some kind of chain brake and that almost all chain saws manufactured for commercial logging operations now have chain brakes (Ex. 5-19; Tr. OR 185-87, 536). In addition, one commenter said that manufacturers have improved earlier mechanical problems with chain brakes so that they are reliable in preventing kickback (Ex. 9-4). With regard to the effectiveness of chain brakes, one commenter said:

The chain brake is, I'd say, one of the most important chain saw protective devices developed in modern history. In Montana all of our current professional saws are equipped with chain brakes. Most of our saws are in the four to six cubic inch range, primarily, Stihl and Husqvarna with a few other minor brands and seldom on job visitations do I find anyone who has disconnected the chain brake. It's so uncommon that it's startling when I find that any more.

The other protective device that I see that's had substantial improvement is the throttle lock mechanism where it has to be held down with your palm in order for the trigger to operate. For years it was common that the first thing a logger did was he got a roll of black tape and he would tape that down so you didn't have to operate that. Through our progressive Montana Sawyer Safety Program and other efforts I brag to people that we now have developed a genetically superior timber faller in Montana that can now squeeze with his palm and pull with his trigger finger at the same time.

These two chain saw protective devices combined with leg protection have had a significant impact on the reduction of accidents in Montana relative to timber falling. In fact, it's been so significant that I don't even consider the other options of even any application to logging when we talk about the low kickback bar, the low kick-back chains and even the bar tipped guards. They may have individual special application but I'm thoroughly convinced with the chain brake, the throttle lock and the leg protection we've so significantly reduced chain saw injuries that any further attention is maybe some wasted effort and just further develops additional conflict (Tr. OR 536).

Mr. David Kludt, Logging Safety Program Supervisor for the State of Idaho, testified that 10 percent of all logging accidents each month are the result of chain-saw kickback and that these accidents could be drastically reduced by the use of chain brakes (Ex. 9-4).

In addition, Maine BLS says that chain brakes have played a significant role in lessening the effects of chain-saw injuries in that State (Ex. 5-174). They reported that only 13 percent of chain-saw accidents where chain brakes were present resulted in hospitalization, while nearly half of all other accidents required hospitalization.

Some commenters, however, disputed the effectiveness of chain brakes for preventing kickback (Ex. 5-39, 5-59, 5-66). One of these commenters said chain brakes were not reliable and required frequent maintenance, however, no evidence or data were presented to support the contention (ex. 5-59). Another commenter said that a study showed that while chain brakes reduced kickback by 80 percent, non-kickback accidents showed a 400 percent increase (Ex. 5-66). However, the commenter also admitted that the study was from 1972 and that chain brakes had undergone significant improvement since that time. Another commenter said chain brakes, depending on their design, could become entangled in the brush the saw is clearing and create a safety hazard (Ex. 5-39). The WIR survey, however, does not support the commenter's argument. None of the chain-saw operators reporting injuries said their chain brake had become caught (Ex. 2-1).

b. OSHA regulatory action. Many commenters said that the final rule should include requirements for chain-saw protective devices (Ex. 5-17, 5-19, 5-21, 5-27, 5-34, 5-42, 5-46, 9-3, 9-4, 9-13, 9-15, 9-18, 9-20; Tr. OR 536-37). However, some commenters, including chain-saw and chain-saw accessory manufacturers, said OSHA should include performance requirements for chain saws in the final standard rather than specification requirements (Ex. 5-4, 5-8, 5-13, 5-15, 5-26, 5-37, 5-59). Many of these commenters supported incorporating by reference the American National Standards Institute (ANSI) B175.1-1985 standard on "Safety Requirements for Gasoline Powered Chain Saws" (Ex. 5-4, 5-8, 5-13, 5-15, 5-26, 5-37, 5-59). The ANSI standard specifies a performance criteria for manufacture and testing of chain saw safety features, such as protection from chain-saw kickback. One commenter summed up their rationale:

[T]he Status Report on Chain Saw Related Hazards since the 1985 Revision to The Voluntary Standard ANSI B175.1, which was prepared for the Consumer Product Safety Commission in March of this year, is a testimonial to the fact that the reduction in chain saw injuries is the result of adherence by manufacturers to the voluntary standard. There truly is little to be said in defense of OSHA when it chooses to knowingly ignore the demonstrated success of the chain saw voluntary standard, which equates compliance with the use of a combination of devices, in favor of an arbitrary and inexpert agency decision to the effect that one specific device, in and of itself, is superior to any other device or combination of devices permitted by the standard (Ex. 5-4).

These commenters stated that OSHA would create "confusion in the marketplace" if OSHA adopted requirements that were significantly different from the ANSI chain-saw standard that all manufacturers have been voluntarily following (Ex. 5-4).

Other commenters, however, opposed incorporating the ANSI standard in the final rule (Ex. 5-27, 5-48; Tr. OR 118). These commenters said the ANSI standard was developed to protect consumer chain-saw users, not professional loggers:

The ANSI B175.1 Standard was developed from an injury data base that was consumer based and therefore its direct application to pro-logging may not be justified (Ex. 5-27).

Two commenters said that ANSI standards were not known to most loggers, were not readily available, and were not written in language that the average logger would comprehend (Ex. 5-27; Tr. OR 118). One of these commenters said OSHA, therefore, should put its requirements in the standard rather than requiring logging employers to obtain and read another document (Tr. OR 118). He added that placing the requirements in the regulatory text would increase compliance.

As discussed above, many commenters supported a requirement that all chain saws be equipped with chain brakes rather than just referencing the ANSI standard. In general, these commenters said chain brakes were the most effective device to protect operators from kickback and to provide extra protection when the saws are carried between cutting jobs. In addition, one commenter supported a chain brake requirement for the following reason:

The U.S. should follow the lead of other countries (European) and require that all saws have an operating chain brake if purchased after the adoption of these regulations. The cost would be minimal since the majority of saws now come equipped with these devices. This would also help deter the disabling of the brake system by operating personnel (Ex. 5-19).

OSHA agrees with commenters that the final standard should include requirements on chain-saw protective devices. The final rule does incorporate by reference the ANSI B175.1 consensus standard, but the Agency believes that the ANSI standard alone does not provide the necessary degree of safety for logging employees. Accordingly, for several reasons, the final rule also requires that chain saws placed into initial service after the effective date of the standard be equipped with chain brakes. First, there is considerable evidence in the record that chain brakes are effective and the most used device to prevent kickback. Second, they have strong acceptance by logging professionals, and as a result, already are standard equipment on almost all chain saws currently manufactured. Third, chain brakes do not have the disadvantages of the other protective devices. For example, unlike bar tip guards, chain brakes are not removed by operators. Unlike reduced-kickback guide bars and low- or reduced-kickback chains, chain brakes do not affect production efficiency. Fourth, other countries also have adopted provisions requiring chain saws to be equipped with chain brakes (Ex. 5-19).

Fifth, OSHA agrees with commenters who are concerned that, in order to maximize compliance, the standard be comprehensible to the average loggers. This is especially important for chain-saw safety, since many employees provide their own chain saws. These employees and their employers need plain and simple direction about what protection must be provided for each chain-saw operator. OSHA does not believe that the ANSI standard contains the type of information needed by those operating the chain saw. It requires the use of sophisticated equipment and exacting procedures that are beyond the expertise of the average logging employer. Much of the ANSI standard deals with a computer program for simulating chain-saw kickbacks and tests to determine the accuracy of the computer program. As such, the ANSI standard is primarily directed to manufacturers of chain saws, rather than employers and employees in the logging industry. For example, the standard states:

The purpose of this standard is to establish minimum safety requirements with respect to the manufacture of portable, hand-held, gasoline-powered chain saws (Ex. 4-66).

The requirements of the ANSI standard are primarily within the unique purview of manufacturers, such as requirements for the throttle control system, handles, pull-type starters, fuel tanks and oil tanks, exhaust systems, sound levels, and vibration. Only the following requirements are directed at the employer:

It shall be the responsibility of the owner to maintain the chain saw in accordance with the instructions in the owner's manual.

Chain saws shall be used in accordance with the operating instructions and safety precautions listed in the owner's manual. It shall be the responsibility of the owner to see that such instructions and precautions are given to every operator who uses the saw (Ex. 4-66).

In addition, the ANSI standard does not require the employer to ensure that each chain saw used in their workplace is equipped with kickback protection. That is, the ANSI standard does not require the employer to ensure that kickback prevention devices are not removed or disabled by operators. By specifying that chain saws used by logging employees be equipped with chain brakes, OSHA emphasizes that responsibility for compliance with OSHA standards rests with the employer, not the manufacturer or the employee.

In order to retain flexibility in the final rule, OSHA is requiring chain saws placed in service after the effective date of this standard to be equipped with chain brakes or other protective device that prevents or minimizes kickback. OSHA notes that whatever kickback device is present, the final rule requires that it not be removed or otherwise disabled.

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