Trial Magazine

A man is catastrophically injured when lowering his boom lift basket between two structural I-beams. His coworkers report hearing a colossal bang before seeing him collapse in the basket. His basket is found pressed up on the underside of the I-beams. He wakes up in the hospital with a broken neck and severe facial fractures.

In another incident, two men are operating a lift between bridge bracings to paint the underside of a bridge. During operation of the lift, the basket becomes stuck on the bridge structure. One man climbs out of the basket to find help. The weight change leads the basket to release, flinging the man in the basket into a structural beam, killing him. Both incidents resulted from a dangerous boom lift defect known as the stored energy defect.

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Few, if any, manufacturers identify the stored energy hazard by name in any of their lift materials. Instead, typical warnings tell the operator to avoid contact with obstacles.

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The Stored Energy Defect

The stored energy defect is often camouflaged under alleged operator errors.¹ For instance, the operator misjudges the distance between their lift and an obstacle, leading to their basket getting stuck or “hung up.”

Credit: OLEKSANDR FILON/GETTY IMAGES

Once initially stuck, any further operation of the platform controls, either to try to free the operator from the obstacle or because the operator does not immediately realize what has happened, causes a dangerous buildup of energy in the aerial lift’s hydraulic system. This energy starts to build as soon as the lift is snared, quickly reaching unsafe pressure levels. If the platform breaks free, it leads to a dangerous catapulting effect, exposing the operator to fall hazards and forceful collisions with other objects.

Understanding this defect requires a baseline understanding of the physics of energy. Potential (or stored) energy and kinetic (or moving) energy are two types of energy that can be converted into one another. Kinetic energy is the energy of motion—when an object or substance is moving, it has kinetic energy. Potential energy is stored within an object based on that object’s position, arrangement, or state. More simply, potential energy exists where an object has the potential to move.²

A way to conceptualize stored versus kinetic energy is to envision a catapult loaded with a boulder. When the catapult is loaded and pulled back but not yet fired, the boulder contains stored energy. Once the loaded catapult is released and the boulder is thrown, its stored energy is converted to kinetic energy—its flight through the air.

In describing the stored energy defect, the catapult is an apt metaphor. Modern aerial lifts move through pressurized hydraulic systems. The lift responds to operator input controls by directing or redirecting pressurized hydraulic fluid into piston cylinders. Hydraulic fluid going into the piston increases pressure, resulting in the lift’s kinetic energy. Pressurized fluid moving into the pistons causes the lift component to move outward; hydraulic fluid leaving the piston chambers will decrease pressure and cause the pistons to retract.

The stored energy hazard arises when an obstruction prevents the normal movement of the pistons, even as pressure builds. When an aerial lift is snagged, if an operator continues to operate the controls­—either because they do not realize they are hung up or are trying to unsnarl the lift—continued control input will lead to greater and greater pressure buildup in the pistons.³

The lift cannot respond to the pressure buildup with kinetic energy (in other words, movement), so the pressure buildup remains as stored energy in the boom. If the lift comes free from the obstruction with that stored energy, the operator basket is the catapult, and the operator is the boulder. The slingshot effect of the operator basket in these conditions can eject the operator, tip the lift over, or slam the operator into nearby obstacles, leading to severe injuries.

Based on my experience, the risk of the stored energy defect occurring increases if the worksite is supplied with inappropriate equipment. A lift that is too large, not the correct type for the work being done, or lacking available safety equipment can increase the risk of operator hang-up in tight spaces. Likewise, operators who are not adequately trained and familiarized with the lift’s operation are more likely to make operational mistakes that lead to hang-ups.⁴

Industry Response to the Defect

Since only a handful of companies manufacture boom lifts, your target product manufacturer defendants will come from a relatively limited list. In addition to the product manufacturers, consider bringing claims against the equipment rental company that rented the lift. In recent decades, major national equipment rental companies consolidated the industry. While some regional, smaller shops exist, most equipment rentals come from just a few major dealers.

Lift manufacturers and dealers are quick to blame operators for these incidents, often mischaracterizing the stored energy defect as pure operator error. However, lift manufacturers have known about this hazard for decades—OSHA has documented stored energy incidents since the late 1980s.⁵ Despite having access to this data—which is at least constructive notice of this potentially fatal hazard as discussed later in this article—often little has been done to mitigate the risk.

Failure to add safety mechanisms. Engineering controls are available that would eliminate the risk. For example, effectively designed contact and proximity detection systems could prevent the buildup of dangerous stored energy. Proximity alarms can alert operators to nearby obstacles to prevent contact before it happens. These systems also limit boom movement if contact is made, preventing the unintended buildup of stored energy. These devices have been technologically feasible since 2005. One lift manufacturer has had patents for such a device since 2012.⁶

Beyond these preventative devices, on-lift operator safety devices help limit operator injury. Overhead guarding has the potential to restrict the release of stored energy once a buildup occurs. For example, overhead guarding could limit the platform’s movement once the buildup of stored energy is suddenly released. This would limit the amount of stored energy that is released, reducing the velocity of the basket and the severity of the incident.

These structural devices could also act as contact-detection mechanisms to limit continued lift movement once contact is made with an obstacle. Such overhead guards were described in international patents as early as 1996.⁷ Since that time, a number of manufacturers have developed some form of occupant guarding structure, such as AFI/Snorkle’s “Sanctuary Zone” and Genie’s Operator Protective Structure. But even on lifts where these structures are available, they are not standard. Rather, these are optional add-ons that operators may or may not know exist.

Failure to warn operators of the risk. While defendants typically blame the operator for the contact and resulting injuries, few lift manufacturers warn operators about this risk. Few, if any, manufacturers identify the stored energy hazard by name in any of their lift materials. Instead, typical warnings tell the operator to avoid contact with obstacles without explaining that getting stuck is dangerous and must be treated as an emergency.

For example, some manufacturers don’t have any on-product warning labels to alert operators to this risk. In one manufacturer’s manual, the company cautions operators only to not “place boom or platform against any structure to steady the platform or to support the structure.”⁸ Another manufacturer instructs operators only to “not contact adjacent structures with the boom.” Neither provides any explanation of the risk involved. Finally, one manual instructs to “rescue occupants” before freeing a stuck machine while another instructs to “remove occupants” before attempting to free a caught platform. Neither, however, explain the risk posed by a snagged boom, the situation’s danger to occupants, nor what the occupants should do while awaiting rescue.

As a result of these failures to warn, operators often are aware that they should not strike nearby obstacles but usually do not understand why. Operators often believe that avoiding contact with nearby obstacles is important only to prevent damaging the lift or nearby property and getting pinched. Because they lack instruction on the stored energy defect, they do not know how dire a boom lift hang-up situation is. Some operators may know about the stored energy defect, even absent being warned, because they experienced a near-miss stored energy incident previously.

Lift manufacturers also typically argue that the lift was being misused at the time of the incident. However, selecting lifts to access high and tight spaces is known and expected by the aerial lift industry. Industry advertising is teeming with glossy photos of men in baskets working under and between fixed structures. There is often no warning or guidance in lift materials setting clearance limits for lift operation. Far from being a misuse, the industry intends that its lifts are operated in limited space.

Failure to train operators and negligent entrustment. Lift dealers, often the only lift industry members to talk with the user and see the worksite, are also responsible for ensuring the lift is the correct tool for the job.⁹ Lifts come in many sizes and heights. Some are already equipped with proximity sensors and overhead guards. Unlike the average lift rental customer, who often has minimal contact and experience with boom lifts, dealers are experts in both their inventory and available safety devices. This gives dealers the responsibility to deploy that knowledge to minimize the risk of stored energy incidents.

In supplying the lift, dealers also have an obligation to make sure they are not entrusting equipment to operators lacking the training and experience to operate it properly. Workers who rarely need lifts are often unaware of the necessity of training and familiarization. Dealers who supply these powerful and dangerous pieces of equipment to unqualified personnel can be found responsible for negligent entrustment of the lift and the resulting injuries.¹⁰

Discovery Strategy

Regardless of your target defendant, the key questions to answer in discovery with manufacturers and dealers are:

• What did they know?
• When did they know it?
• What did they do in response?

Manufacturers. For manufacturers, determine when they learned about the stored energy defect and their understanding of it. Discovery of other similar incidents can help solidify that they knew about the risk posed by the defect. If you can establish the existence of other similar incidents, it is critical to nail down whether they made any changes to their design or policies after each incident. A history of ignoring these instances demonstrates an indifference to the risk.

Also ask about the availability of contact and proximity sensors on their lifts. Some manufacturers have these products available as safety options for their devices already. Inquire as to why these were not made standard. You want to know what efforts they made to address the stored energy defects in their lifts.

Determining how the manufacturer intended their lifts to be operated is also essential. Did the manufacturer have any minimum clearance distance requirements for lift operation? If so, how were those communicated to operators and users? Did they know that their lifts were being operated in areas like the one in your case? Was that operation permitted or not? If they contend it was not, how were those operational limitations communicated to operators and users? Did they change their clearance requirements due to the stored energy defect? These questions aim to determine whether your client’s operational parameters were, from the manufacturer’s point of view, a proper use or, at the very least, a foreseeable misuse of the lift.

Dealers. For dealer discovery, focus on the dealer’s knowledge of the worksite, how the lift would be used, who would be operating it, and whether the operators were trained and qualified. Establish what kind of information the dealer requested from the customer during rental and delivery. Dealer knowledge of the worksite and any environments that increased the risk can be established through sales representatives’ visits or when the lift was delivered.

Discover the dealer’s policies concerning job hazard assessment, working with customers to identify the correct tool for the job, checking for operator training before delivering and turning over lifts, and worksite assessments. Did they require their sales and delivery people to get this information, and for what purpose? If so, did they comply with that requirement here? If not, why not, and was there anything preventing the successful implementation of such a policy?

Confronting Industry Defenses

Recent changes to the ANSI boom lift standards have lowered the industry requirements for dealer conduct.¹¹ These changes, however, do not eliminate state law tort claims. The Restatement (Second) of Torts provides several avenues to establish common law duties for dealers, including §§324A, 388, 390, and 392. If your state has adopted these sections, they provide a clear avenue for establishing a duty, even under the current ANSI regime.

Expert testimony is critical to establish the design defects, warning failures, and the dealer’s obligations during rental and delivery. Make sure you have discrete experts to handle each of these components. A mechanical engineer must discuss the stored energy defect, the manufacturer’s knowledge, and alternative designs. A human factors expert should review the warnings and establish whether they were sufficient.

A construction site or operational engineer is required to assess the conduct of the rental company and whether it complied with industry requirements. This expert can also comment on the operational training your client received and whether it was appropriate for your client to be in the lift in the first place. Use caution when considering having one expert comment on more than one of these areas. Setting aside Frye and Daubert challenges, separating experts in this way allows for clean piecemeal settlements in case one of the defendants is willing to reach a settlement before another.

Finally, it is vital to understand your client’s background with the lift and the stored energy defect. Learn whether your client was aware of the stored energy defect. You need to establish whether your client knew that they should avoid lift contact with obstacles and also whether they knew the specific risk those obstacles posed. If applicable, do not shy away from your client’s limited aerial background. Insufficient training is a good fact for your case—it is easy to understand a client’s mistake when they have been poorly trained and lacked the necessary information about the stored energy defect.

At first glance, stored energy hazard cases can hide under the guise of pure operator negligence, but the true cause often lies in products liability and negligence. Don’t let the boom lift industry off the hook for its failure to adequately protect and warn against these avoidable incidents.

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Elizabeth Bailey is of counsel at Grant & Eisenhofer in Wilmington, Del., and can be reached at ebailey@gelaw.com.

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Notes

1. Int’l Powered Access Federation, MEWP Catapult Effect, https://tinyurl.com/yc2zha72.
2. U.S. Energy Info. Admin., What is Energy?, https://www.eia.gov/energyexplained/what-is-energy/forms-of-energy.php.
3. Id.
4. For more, see David L. Kwass, Looking Out for Boom Lift Defects, Trial, Nov. 2017, at 40.
5. These incidents are archived on the OSHA website. Materials outlining these incidents were accessed by going to https://web.archive.org/https://www.osha.gov/oshstats/. Type the URL as one URL, then click on the “captures” link in the top left corner. Select archived pages from Feb. 3, 1999, or Aug. 15, 2000, to access the databases.
6. Safety Device for an Aerial Lift, U.S. Patent No. 20130153333-A1 (filed Nov. 29, 2012).
7. See, e.g., Safety Device in Work Table in High Lift Work Vehicle, Jap. Patent No. JPH107398A (filed 1996).
8. Manuals discussed in this paragraph are on file with author.
9. For more, see David L. Kwass, Heavy Lifting Ahead, Trial, Nov. 2019, at 46.
10. See, e.g., Restatement (Second) of Torts §§388, 390, 392 (Am. Law Inst. 1965).
11. New ANSI standards were put into place, applicable to conduct in 2020 onwards, that removed industry requirements for dealers to ensure they were supplying the correct tool for the work, providing familiarization, and ensuring intended operators were trained before delivery of the lift. Under the new suite of standards­—A92.20, A92.22, and A92.24—rental companies were tasked only with ensuring proper maintenance of the machine. See also Kwass, supra note 9.