Trista Hamsmith was motivated to seek changes in legislation to consider how children might access batteries and address risks inherent in products used by children. If companies are not required to make their products safer in a specific way, they might not adjust.

Previous federal battery legislation including EPA’s Universal Waste Rule (1995) and the Federal Battery Act of 1996 focused on labeling and recycling of nickel-cadmium (Ni-Cd) and certain small, sealed lead-acid (SSLA) rechargeable batteries. The purpose of these regulations was to reduce the environmental impact of consumer batteries, increase and standardize battery recycling efforts across the nation, and to phase out the use of mercury in batteries. ⁵ While these regulations made steps in the right direction, they did not legislate safety regarding battery packaging and warning labels that could protect a toddler like Reese. Reese’s mother understood firsthand that this regulation was insufficient and began a quest to create a system that would protect other children from the dangers of swallowing batteries.

In addition, at this stage of brain development for children, they are incapable of processing the full risk of their actions. When a child is choking, there are several outward signs such as gagging, gasping, or the child’s complexion changing color that will spur a parent or caretaker to take emergency actions. However, if a child swallows a battery, there are no immediate emergency conditions such as gasping for air; the caretaker might not realize they swallowed it and that there is an emergency, even though the internal results are devastating.

By design, all batteries, regardless of chemistry or size, share a physical characteristic: a separation between the cathode and anode. This separator, when physically connected by other conductors to complete a circuit, allows a battery cell to discharge and power many of our products. A conducting liquid, such as saline or mucus in the esophagus, is enough to complete the circuit. If a child swallows a battery, the completed circuit produces sufficient current to burn adjacent tissue. Tissue damage begins almost immediately, with permanent impact in 15 minutes and fatal impact in as few as two hours. Larger button-cell batteries (≥20 mm diameter) cause even stronger burning reactions. ³ In Reese’s case, the 20 mm battery eroded the esophagus and burned into the airway. Even after the battery had been removed, her tissue was damaged so severely that it could not be repaired after several surgeries. After 40 days on a ventilator, Reese succumbed to her injuries and passed away.

Reese’s Law mandated the development of a compulsory safety standard for button-cell or coin batteries and consumer products that contain such batteries. Signed into law in August 2022, the Federal Consumer Product Safety Commission (CPSC) then had 12 months to work through the process. By February 2023, CPSC outlined the requirements for the standard and then evaluated the potential for any safety standard-setting organizations that might already have a safety standard in place that met their requirements. They found no existing standard that met all of the new safety requirements. 

Simultaneously, UL Standards & Engagement realized that UL 4200A could be updated to meet the new requirements of Reese’s Law. UL 4200A was originally created to standardize the safety for products incorporating button-cell or coin batteries of lithium technologies that are not actually toys. (Toys for children must meet a different safety standard, ASTM F963, the Safety Standard for Toys.) This prompted ULSE to assemble an advisory team of experts, called a technical committee, to revise UL 4200A to meet the new requirements in Reese’s Law. As part of the ULSE process to publish a safety standard, the interdisciplinary technical committee (called TC 4200) would need to reach consensus on various trade-offs between product safety and expense from multiple standpoints such as battery manufacturers, transportation and shipping, and product design. ULSE’s consensus-building process of drafting, circulating comment copies, and collectively resolving any outstanding issues for publication can take years. TC 4200 only had six months. 

This iterative process included consideration for establishing a standard that defines terms and scope, establishes battery compartment construction requirements for both operable and inoperable battery compartments, establishes how the battery compartment functions when used or misused, and describes required safety warning labels with emergency contact information.

TC 4200 defined the terms and scope first using CPSC’s 14 requirements, which included necessary enclosure-closing and opening mechanisms. TC 4200 also decided to address the need for products containing button-cell batteries to remain secure during use and during product disposal. The revised UL 4200A scope would include products that were specifically not toys but still posed considerable risk. As an important detail of the scope of the standard, it might be additionally relevant to note that this standard excludes button-cell batteries using zinc-air chemistry, such as hearing aid batteries. If this type of battery was swallowed, no air can reach the battery, and thus its voltage-producing chemical reaction ceases. 

After defining terms and scope, UL 4200A describes required construction for battery compartments that are operable (in which batteries could be replaced by the user) and those that are inoperable (in which the battery is not replaceable). Like many safety standards, UL 4200A states the limits for successfully passing a viability test. Viability tests are specific tests listed in the safety standard that test whether the product would work successfully for these requirements. If the product can pass this test, it may be certified. As written in UL 4200A, if the battery compartment is to be opened, then it must require an adult force on a tool or adult coordination (two-handed opposing motions) to open. For example, certain calculators might have a separate compartment for a button-cell battery under the compartment for AA batteries, which requires a small screwdriver to open to replace that battery. 

If the button-cell battery’s compartment is supposed to remain closed, then it must comply with ASTM F963, a safety standard for toys that children use, which establishes the standard that it cannot be punctured or opened with less than an adult force (7 N or 15.7 lbf). Whether operable or inoperable, UL 4200A also states that a probe cannot contact the battery from outside the product, ensuring a curious kid cannot pry it out.

UL 4200A continues by stating how the compartment must perform when used or potentially misused by a child. Through a range of abuse tests, the product should withstand being dropped, struck by a horizontal force, crushed by a vertical force, and pried by a hook. 

Finally, UL 4200A states that products and packaging should include permanent warning labels with symbols and text to inform consumers about the presence and danger of a button-cell battery and who to call if a child swallows a battery. Directive symbols and text are mandated in the standard, such as “Keep new and used batteries out of reach of children” and “Death or serious injury can occur if swallowed.” Depending on the size of the product, different truncated statements are indicated. Several permanence tests for markings are provided including number and strength of rubbing motions with a wet cloth and with mineral spirits.

The technical committee met weekly for three months. They utilized ULSE’s Collaborative Standards Development System, writing, inviting public comments, revising, and balloting the proposed revisions to come to consensus. On August 15, 2023, one day before the CPSC deadline, ULSE published UL 4200A, which met 13 of the 14 requirements. With CPSC’s approval, UL 4200A was revised again on September 11, 2023, meeting all 14 of the requirements. By publishing within five months, the committee members achieved a rare feat; they created a standard to accompany legislation in record time, and provided manufacturers with certification tests to ensure their products would not release dangerous button-cell batteries while in use or in the hands of children. 

Trista Hamsmith continues to work with battery manufacturers to do more to safeguard children from button-cell batteries. In 2024, she collaborated with a major battery manufacturer to implement a three-part battery technology including packaging that requires each button-cell battery’s plastic bubble pouch to be cut open individually in a circle, a bitter-tasting coating, and a saliva-activated blue dye. As of March 19, 2024, products with button-cell batteries must meet UL 4200A, and further battery packaging requirements began on September 21, 2024. Beyond working with the battery manufacturers, Hamsmith is also advocating for amendments to Reese’s Law that would mandate a dye coating on button-cell batteries. If that amendment passes, then safety standards organizations like ULSE will again work collectively to update safety standards so consumer products can demonstrate their safety by meeting the highest safety standards available.