From being a Halloween staple, to high-stakes military missions, glow sticks are a common and versatile light source used worldwide. Despite their popularity, new research are associating their use with serious health and environmental hazards that require urgent attention.
Traditional glow sticks have two compartments: one contains hydrogen peroxide, and the other holds a fluorescent dye and a small glass vial. When the stick is bent, the glass vial breaks, allowing the substances to mix, triggering the light creating reaction.
These sticks were originally developed by the US Military, and were originally powered by chemicals that are now illegal [1]. Regulations have forced manufacturers to change their formulas; and glow stick companies have marketed these changes to promote their glow sticks as safe and non-toxic [2]; however, there is little, to basically no evidence, that shows that the new formulations are as safe as glow stick companies promote them to be [3]. In fact, there is increasing evidence that shows them to be alarmingly dangerous.
An increasing volume of scientific research reveals alarming toxicity levels following exposure to post-activation glow stick liquid [6, 7, 8, 9, 10], indicating the generation of harmful by products. Furthermore, consumer reports have unveiled a troubling reality: the majority of commercially available glow sticks contain undisclosed ingredients. Out of 20 surveyed glow sticks, 17 were found to contain outlawed chemicals [8].
With the staggering number of glowsticks every year, the toxic constituents in their formulas, the alarming aftermath of their use, and the sneaky loopholes that companies use to label glow sticks as ‘safe and non-toxic’ are increasingly concerning, making the need for safety and sustainability more pressing.
Light sticks available on Amazon, labelled as Non-Toxic and in the description as "Child Friendly" [4].
Contains dimethyl phthalate (DMP) and butyl benzoate [4]. DMP, an endocrine disruptor, can cause reproductive issues and since 2017, similar phthalates have been banned in children's products [5].
Note on language used in this report:
If you search online for ‘glow stick chemistry’ usually the term ‘chemiluminescence’ is used. By definition, chemiluminescence refers to ANY chemical reaction that creates light. The reaction that occurs in glow sticks is just one type of chemiluminescence. So in order to keep definitions straight, we will use the terms ‘chemical light’, ‘glow stick formulations’ or ‘glow stick fluid’, to distinguish this topic from the more general term ‘chemiluminescence’. Most chemiluminescence is very dim - it took a lot of work and intensive chemistry to get glow sticks so bright.
1. Dioxins and “Agent Orange” in Original Glowsticks
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Agent Orange survivors marching for awareness and support - many here are living with the long term impact of dioxin exposure.
Historically, the first glow sticks made in the 1970s were extremely hazardous. They contained ‘polychlorinated oxalate esters’ that, when reacting with peroxide, could form TCDD (tetrachloro dibenzo-para-dioxin), the worst known dioxin. It is this dioxin that made the now-illegal chemical weapon, Agent Orange, as dangerous as it is [1].
TCCD is a by product that would only appear after the glow stick was activated, making it difficult to detect in pre-activation tests. It is after the glow stick is activated that these by products were made, and how the dangers in glow sticks went unnoticed.
Dioxins are persistent, carcinogenic, endocrine disrupting molecules. Short-term exposure to dioxins can cause skin lesions and impaired liver function. Long-term exposure is linked to birth defects, impaired immune system, altered development of the nervous system, the endocrine system and reproductive function. It is a persistent pollutant that can impact generations of people after exposure [1]. Superfund sites are polluted areas that are designated for urgent clean-up as they pose urgent risks to human health and the environment. The first 'superfund site' in the United States was caused by TCDD contamination, which became known as the Love Canal Disaster [11]. Families were forced to flee their homes, after a drastic increase in rare cancers that were linked to environmental TCDD exposure. Love Canal remains uninhabited today.
Regulations banning the use of these chemicals pushed glow stick companies to develop alternative formulations, and this is what led to ‘modern’ formulations. The changes are very small on a chemical level. As far as we can tell, research surrounding whether dioxins are forming in current formulations is not fully completed, or not made publicly available. Although different molecules will have different mechanisms of action, just because it is not as selective for what TCDD targets, does not automatically mean they are any less dangerous.
The current standards in glowstick formulations use what are considered to be ‘polychlorinated oxalate esters’: CPPO - Bis[2,4,5-trichloro-6-(pentyloxy carbonyl)phenyl]oxalate and TCPO - bis(2,4,6-trichlorophenyl), which are expected to react with hydrogen peroxide. It is the chlorinated species which are most likely to create any number of dangerous by-products. There is growing evidence that has found surprising toxicity, discussed in section 2. The results from these studies are becoming expected, as authors noted in this paper [6].
It is noteworthy that there is no evidence publicly available that strictly confirms that dioxins are not formed by the new formulations. It seems that glow stick companies would be promoting this chemical safety data as widely as possible if the chemistry was conclusive.
There may be a mechanism that produces dioxins as a byproduct of a reaction with the new chlorinated molecules in new formulas. We are working to investigate this matter with help from academic partners, as this has yet to be characterized.
2. Health Risks: Modern Formulations and Designs are still Hazardous!
The active reagents in chemiluminescent products are anthracene and oxalates synthesized with dibutyl phthalate. Dibutyl phthalate has been reported to cause anaphylaxis [6], and even death when ingested in large quantities [7]. Reports of exposure to these chemiluminescent products are scarce and their toxicities and outcomes of exposure are essentially undescribed.
In response to a dramatic number of incidences of exposure to chemiluminescent products reported to poison control centers [12], we sought to examine the risks and outcomes of exposure events. A 2014 publication in Nature outlined how exposure to the byproducts of chemiluminescent reactions causes cell death and genotoxicity, even at low concentrations [6]. The Latin American Journal of Aquatic Research, classified the chemical waste from glow sticks as ‘exceptionally toxic’, after determining the LD50, or the lethal dose of a substance that leads to expected death in 50% of a population of different organisms. The LD50 was 0.001% for shrimp populations, and more research found that exposure to glowstick byproducts reduced crab hatchability by 100%. Not a single egg survived [13].
Boxplot of lethal concentrations (LC50). 0.001% of light stick fluid causes mortality in 50% of the exposed population of shrimp-like organisms after three hours of exposure [13].
If glow stick liquid remained inside its tube, the risks of exposure would be less worrisome; however, over the past ten years, 2.4 million people in France alone have called poison control centers after exposure to glow stick liquid. 50% of the calls were from parents with children between the ages of 1 to 4, who had bitten into a chemical light stick and had swallowed the liquid inside.
Another concern comes with the encasement of glow sticks. Modern formulations have not changed how glow sticks are activated, and the plastic and glass encasement of components. Hospitalizations often occur when broken glass is ingested accidentally, or makes contact with eyes. The glass can shred stomach linings or corneas, creating direct exposure to the chemicals. Unfortunately, most poison control centres respond as if the liquid is minimally unsafe [14] - part of our work is helping raise awareness of the research done within the past ten years that points to the chemical by-products being extremely dangerous.
5. Well over 1 billion units every year of non-recoverable, toxic, plastic waste
2.4 million glow sticks were removed off Australian Beaches by volunteer collectors with the Tangaroa Blue foundation. This represents only the waste from the commercial fishing industry alone over the past 20 years [12]. Apart from the fishing industry, glow sticks are used extensively in holiday celebrations, festivals, first aid kids, outdoor activities, diving and military operations. They are often discarded, polluting the environment, and even if they end up in a landfill, they are non-recyclable and there exists no waste recovery options for glow sticks.
Glow Sticks left behind in a parking lot. The durability of plastic products enable them to persist for long periods in the environments, where they end up in oceans or release microplastics leading to potential ecological risks [15].
Traditional glow sticks have two compartments: one contained in a small glass vial. When the stick is bent, the glass vial breaks, allowing substances to mix, triggering the light creating reaction. Due to the use of broken glass, processing the substances is difficult, as it would require cutting open the stick, safely separating the liquid, glass and plastic, and recycling each component. Currently, no recycling centre accepts glow stick waste, including Terracycle, who is known for accepting the most hard to recycle objects, such as cigarette butts and used batteries [16]. Used glow sticks contain a mix of hazardous chemicals and shattered glass, which makes both the glass and the plastic non-recyclable waste. Even if proper disposal of glowsticks existed, their contents and packaging do not allow for a natural breakdown, leading to the contents leaking into surrounding soil or water, and polluting the environment. Plastic debris, including from phthalates and phenols, leak out of plastic objects into marine environments, and there are concerns that long-term, low-level exposures can lead to nonlinear effects, including endocrine disruption, cancers, developmental disorders, and reproductive abnormalities [17].
In the best case scenario, they are transferred directly into a sealed dark box to prevent UV exposure, and then disposed of as hazardous waste. However, this is not currently standard practice, and many are discarded in landfills. Unfortunately many glow sticks do not even make it to landfills - they routinely pollute our lands and oceans. This is what initially prompted original research into glow sticks in Brazil, where researchers were able to collect over 6000 glow sticks used as pelagic attractants, or fishing lures, that had washed ashore [6]. We estimate that well over 1 billion glow sticks are made every year, becoming more toxic over time, with the plastic and chemical waste remaining in the environment forever. This represents 10.6 million litres of these dangerous chemicals entering our environment, getting into our waterways.
4. Unseen Hazards: Glow Stick Toxicity Increases Over Time and with their Activation
We have seen that glow sticks cause harm to human health and the environment. Recent investigations have shown that this toxicity of glow stick formulas may intensify over time, posing new, unforeseen risks.
In 2014, Nature Science Reports released “Luminescent Threat”, which was one of the first pieces of academic literature that studied the toxicological impact of chemical light fluid on cell lines [5].
Researchers collected 6,000 glow sticks that had washed ashore on a beach in Brazil. Investigating the glow stick’s post-activation fluid revealed that post-activation fluids showed acute toxicity, even in modern glow stick fluid formulas. Researchers initially had difficulty investigating if these substances caused genetic mutations, as the post-activation fluid was cytotoxic and caused complete cell death, making it impossible to determine if mutations occurred in the cells before they died. After diluting the post-activation fluid 30,000 times, it was found that exposure to glow stick fluid caused genetic mutations in human cell lines [6].
Increased exposure to sunlight over time has also been shown to increase the toxicity of these compounds. Research indicates that after prolonged sunlight exposure, products, catalyst, and solvents involved in reactions experience an increase in toxicity [5]. Since humans are mainly exposed to activated light sticks, extrapolating toxicity data from the initial components—before activation and sun exposure—can be misleading. This highlights how companies may focus on the toxicity of the unmixed contents, overlooking the real danger that emerges after glow sticks have been used and exposed to sunlight [4].
The “spikes” in the images above correspond to the chemical mixture of the formulas analyzed. The above image shows a glow stick formula after 4 days, where the lower graph shows a glow stick collected after sitting on a beach for a longer period of time. Over time, we can see that new ‘spikes’ have developed. These new spikes indicate that multiple by-products, not present in the initial reaction, have formed over time.
Research has made it evident that by-products of the glow stick reaction, especially after being exposed to UV rays, temperature fluctuations and being lost at sea for years, have led to increased toxicity. Since the publication of this 2014 paper, a growing body of evidence is further confirming and expanding on their results [7, 8, 9, 10].
When glow sticks solutions are mixed, TCPO reacts with hydrogen peroxide, yielding 2,4,6-trichlorophenol and an highly energized 1,2-dioxetanedione intermediate, whose DPA-activated decomposition to CO2 places the fluorescer in the fluorescent state. The chlorinated product created, 2,4,6-trichlorophenol, is listed by the US National Toxicology Program as reasonably anticipated to be a human carcinogen, and by the US Environmental Protection Agency 15 and the International Agency for Research on Cancer, as a probable human carcinogen [6].
More recent studies have identified a myriad of harmful by-products, including 2,4,6-trichlorophenol, as well as polychlorinated dibenzodioxins, known for being carcinogenic and impacting normal development [8]. 2,4,6-trichlorophenol is a specific chemical in the chlorophenol family. As the Nature study outlines, once “chlorophenols are absorbed through ingesting/biting, skin contact, and/or the fumes breathed in, both local and systemic effects are expected. After absorption, major concentrations of chlorophenols have been reported to be found in the kidney and liver for up to 20 days. Chlorophenols are liver tumor promoters [6].”
Another scientific paper investigated a step further into the impact of time on the toxicity of the formulas, and found that exposure to formulas that were 1 year old resulted in 2 times more toxic effects than exposure to glow stick formulas that had just been activated [7]. This research also tested the exposure to the separate components of non-activated glow sticks. They found that separate components had much lower toxicity compared to the fully mixed formula. Again, it was suggested that the increase in toxicity over time could be attributed to the creation of by-products of the reaction, which is of particular concern, as this is not outlined in consumer resources.
The authors of Luminescent Threat couldn’t summarize it better: “An urgent need exists to adequately manage the discarded [light sticks] and to foster awareness about the health risks that may result from exposure” [6].
5. Legal Violations:
Regulatory Loopholes and Gaps
Inadequate adherence to legal regulations, as well as regulatory ambiguities exist despite the presence of toxic and dangerous components in glow sticks.
For commercial glow sticks, components of the formulas are not required to be listed on the outside of glow stick packaging, making testing commercial glow stick formulation or making specific claims regarding their contents or origins difficult. To make matters worse, there is growing evidence that the leading chemical lighting companies routinely break chemical regulatory laws.
Europe’s REACH regulations mandate the manufacturers have to provide information about the substances contained within their products to regulatory authorities, even if they are not explicitly mentioned on the packaging [19]. Based on the self-reporting, the Danish Ministry of the Environment launched an investigation into glow stick products, and the findings were shocking. Illegal chemicals such as dibutyl phthalate were found [19], and only 3 out of 20 products surveyed properly self-reported the chemicals used in their formulations, and 17 out of 20 had different and often more dangerous formulations than reported [12].
Another concern surrounds the specific regulatory language around the “accessibility” of toxic components of a product. Loopholes around this have come to public attention in the United States, when the viral Stanley cups, mugs used to hold liquid meant for consumption, were found to contain lead. The manufacturers were not breaking any laws, because the parts containing lead were only deemed accessible if the cover on the bottom of the tumbler became detached or damaged, and therefore deemed inaccessible to consumers and therefore not breaking any laws [20].
The most vulnerable groups, younger children, constituted the majority of registered exposed persons, with 85% due to oral exposure, often due to biting through the plastic tube [10].
This same type of loophole is how glow stick companies can market their product as safe and non-toxic. Currently a child's toy can be marked as “phthalate-free” if the components that contain phthalate are deemed to be inaccessible by the ‘strength of an average 8 year old’ [21].
However, the toxic components are not completely inaccessible in glow sticks. Between 1999 and 2020 there were 2,029,714 exposure events recorded in France alone [12], with 85% categorized as oral exposure, 13% as eye exposure, and 5% as skin exposure. With these high numbers, and millions of calls to poison control centers worldwide, it seems clear that glow stick components are easily accessible.
6. Regulatory Gaps Enable Misleading Marketing of Glow Sticks as 'Safe' and as Toys
Glow sticks are often thought of as safe kids toys - and are promoted this way. Sellers of glowsticks often list their products as “safe and non-toxic”, and many list them as “suitable for children”, and are advertised as party toys, lollipops, necklaces, wands and toy spinners. There are glow stick lollipops available that use glow sticks as the handle of a candy, where the child is able to bite into the candy, while holding the glow stick. This is clearly concerning, by having an edible product near to a glow stick that can be easily bitten into and opened. Some trends include “sensory glow stick baths”, which has alarmingly grown in popularity with parents. Parents may not understand the potential dangers of these glow sticks, due to marketing and legal violations, and young children are more unlikely to not understand the potential dangers that could occur if they break open the glow sticks, leading to exposure, as they see them as toys.
This is especially concerning for children, as components in glow sticks include endocrine disruptors that can be especially harmful to children. These components may be in low doses, but during younger ages, especially during fetal development and infancy, these disruptors pose a higher hazard [19].
Appendix 9 in the Danish Ministry of Environment’s report of glow sticks discussed the concerning marketing targets companies use to target children as consumers. For example, one brand had children on the packaging, despite explicitly having written "not for children'' on the back of the packaging [12].
Given the presence of such concerning chemicals in similar products, it would be reasonable to expect that other glow stick manufacturers would make it easier for consumers to access Safety Data Sheets. However, obtaining Safety Data Sheets for other glow stick products has proven difficult. For instance, a popular lollipop-shaped glow stick toy, advertised for children, is advertised as being made of "safe, kid-friendly materials for worry-free play," yet we were unable to find any information about its components [22].
This is especially concerning, as we have seen that by-products of the activation reaction are toxic, and that toxicity increases with time and exposure to different environments. The marketing used by these companies, paired with the dangers of these products, sends alarming mixed messages to consumers, and is a clear disregard of children's safety.
7. The Need for Alternatives
Glow sticks play crucial roles in many valuable applications. For Coast Guard search and rescues, glow sticks are used to help find someone lost at sea. They are thrown directly into the water to create a ‘cookie crumb’ trail that drifts with the currents; these trails allow rescuers to follow wave movements to locate lost individuals.
Many industrial applications require the use of non-electric lighting. Innovations such as battery powered LEDs have been widely available since the 1990s; however, according to the Chemical Light Stick Source Reduction Plan by Tangaroa Blue and Ocean Watch Australia [18], the use of glow sticks or "light sticks" is often required as they are non-electric, non-explosive, non-battery powered, inexpensive and can be activated nearly instantaneously.
Glow sticks are referred to as 'chem lights' or 'light sticks' in industrial settings, and are chosen for their cold-light, storage life, low cost, and ability to generate light without an explosion risk.
Chemical lighting, with all its flaws, is still incredibly useful.
Glow sticks were designed for single-use, allowing for inexpensive and high-volume manufacturing due to their simple components compared to LEDs. The chemical reaction in glow sticks also produces no heat, making them ideal for military covert operations where a detectable heat signature must be avoided. Since glow sticks don't rely on electricity to emit light, there's no risk of sparking explosions, making them safe for use in environments where electrical equipment is prohibited. They are also the only recommended light source to use after an earthquake or similar disasters, mitigating the risk of explosions from broken gas lines, as they don't rely on electricity. This is also useful when handling explosives, and also in the event of a gas leak. For underwater use, glow sticks can handle significant pressure, and if one breaks, damage costs are not as large as most underwater rated LEDs. Due to their underwater convenience, hundreds of millions of glow sticks are used as commercial fishing lures every year. Widespread adoption of other alternatives, requires concerted action from manufacturers, consumers, and policymakers, and many available technologies have significant drawbacks or simply will not work to replace glow sticks.
In their comprehensive investigation into reducing chemical light stick usage, the Australian government in 2021 determined that no available solutions currently exist. They outlined what would solve the problem - a non-toxic and marine biodegradable glow stick alternative, with the same performance as chemical light, but would quickly degrade in the environment and would pose no risk to human or marine life [12].The solution would need to be inexpensive, easy to use, and basically a rebuild of current glow sticks with completely redesigned materials and chemistry. In the report the writers wondered if something could be done with bioluminescence - how living creatures create light in their cells - something often seen in marine species.
New technology built to solve
this problem
Lux Bio Lume - a marine biodegradable / home compostable glow stick alternative powered with bioluminescence, engineered to address all concerns with the chemical light industry
This is what our company, Lux Bio, has set out to do. In 2021, Lux Bio was founded and with the support of an incredible team, we have developed a breakthrough in the field of cell-free bioluminescence, meaning we have created a completely non-toxic luminescent system. We genuinely love the magic and curiosity that chemical lighting inspires. We even found out that the whole chemical light industry was originally inspired by bioluminescence - the technology just didn't exist before to do what we are doing. So now that incredible advancements in the field of biotechnology have made this possible - its time to go back to what inspired the industry from the beginning. We want everyone to have a safe and sustainable option, for everything from birthday parties to military applications, and beyond!
At its core, bioluminescence is the result of an enzymatic reaction. Our bioluminescent formulas are based on these incredible enzymes, which we can grow in our lab! The bioluminescence reaction requires NONE of the chemicals which are used in glow stick fluid. We simply mix our formula in water and the reaction takes place.
With the support of incredible advancements in the biomaterial industry, we are able to encase this reaction in certified marine biodegradable materials and home compostable packaging. This means that if our glow sticks end up in any environment, from the ocean, to a forest floor, microbial activity will quickly compost the materials. Everything becomes microbe food!
We have learned through this process that although science is challenging, these type of advancements are readily possible. Every product that you see in the store that is packaged in plastic is only done so because it is cheaper for the company producing it to keep using plastic, or to keep using harmful chemicals.
We are dedicated to providing an entirely new class of single-use glow sticks to the world - as an example of what can be done across every industry. If we can make compostable, non-toxic, beautiful glow sticks - what can’t we do? So often the changes we need to see in the world are only blocked by corporate greed - not because amazing technologies are impossible. In fact, many are already solved, and are struggling to find their foothold in the market.
It is hugely costly to start a materials company - from the R&D to figuring out how to manufacturer it, to building new production lines and facilities, and trying to find customers willing to buy something more expensive in the beginning to help bring the scale needed to bring costs down. Unfortunately this is the path new materials need to take, while huge corporations are buying the cheapest, most dangerous materials, making massive profits, and getting away with harming people and the planet.
This is what we are up against.
So for every one of you who helps share our work, share this report, buys our replacements, just know that you are an essential part of us having any chance of changing this industry. Thank you so much for making it this far - lets change this!
Holding an early LUME prototype while overlooking the Vancouver city line.
Now you know too. Lets change this together.
There's more!
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Share this report with your friends, families, and colleagues →
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Collect any glow sticks you find while out and about (once you start looking they are EVERYWHERE) and send them to the Glow Stick Initiative - a non profit who is raising awareness about the glow stick waste issue: www.theglowstickinitiative.org
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Support Lux Bio - one of the best ways to change something is to create something better. More than raising awareness, together we can make sure that glow stick companies, the industries that rely on glow sticks, and the millions of people every year who use these fun, but dangerous glow sticks still has a light they can rely on.
References
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19. EurActiv. (2018, February 23). EU’s new rules to prevent harmful chemicals in children's toys. Retrieved from https://www.euractiv.com/section/health-consumers/news/eus-new-rules-to-protect-children-from-harmful-chemicals-in-toys/
20. Austin, D. (2024, January 24). Do Stanley cups contain lead or pose a risk of lead poisoning? Experts weigh in. *NBC News*. Retrieved June 3, 2024, from https://www.nbcnews.com/health/do-stanley-cups-contain-lead-pose-risk-lead-poisoning-experts-weigh-rcna68276
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22. ArtCreativity. (n.d.). *ArtCreativity lollipop glow sticks for kids - Set of 12 top spinner light sticks - Glow stick light up party favors that double as gyro top spinners - Glow wand light spinners for Wonka party*. Amazon. Retrieved June 3, 2024, from https://www.amazon.com/dp/B09K6T8T8F