Hot glue, a common household and craft adhesive, is known as a thermoplastic adhesive because it melts when heated and solidifies as it cools. When considering the question of toxicity, the straightforward answer for standard craft hot glue is that it presents a low chemical toxicity risk. The materials used in its composition are generally considered non-poisonous under normal use conditions. However, this low chemical hazard is immediately overshadowed by a significant physical danger: the extreme heat required for its function. The primary risk associated with using a hot glue gun is not chemical poisoning but the potential for serious thermal injury.
Chemical Composition and Toxicity
The majority of standard hot glue sticks are primarily composed of Ethylene-Vinyl Acetate, or EVA, a thermoplastic polymer. This EVA copolymer, particularly the formulation used in hot-melt adhesives, is considered a non-toxic and inert plastic when in its solid, cooled state. Other components often include various tackifying resins and waxes, which are added to improve stickiness and handling, and these are also typically non-hazardous.
Accidental ingestion of a solidified piece of hot glue, particularly by children, is a concern but rarely results in chemical toxicity. While the material may cause mild gastrointestinal irritation, the main danger is physical. Since the glue is a plastic polymer, it can present a serious risk of physical obstruction or a choking hazard, especially if large pieces are swallowed. Non-standard or industrial-grade hot glues may contain different additives that could increase the chemical risk, so users should always check the Safety Data Sheet for specific products.
Risks Associated with Inhalation
When the glue is heated in the gun, it releases vapors or fumes that can affect the respiratory system. These fumes are classified as Volatile Organic Compounds (VOCs) that are released as the polymer softens and melts. Inhaling these vapors can lead to irritation of the eyes, nose, and throat, even when the glue is being used at the manufacturer’s recommended temperature. Individuals with pre-existing respiratory sensitivities, such as asthma, may experience a more pronounced reaction to the fumes.
If the hot glue is overheated, the chemical compounds can begin to thermally decompose. This decomposition process releases a more concentrated mixture of organic materials, which may be more irritating or potentially toxic. The primary way to mitigate the inhalation risk is to ensure the work area has good ventilation. Opening a window or using a fan to circulate the air can significantly reduce the concentration of VOCs in the breathing space.
Primary Danger: Thermal Burns
Hot glue guns typically operate at temperatures between 250°F and 400°F (120°C to over 200°C), which is hot enough to cause immediate tissue damage. The molten glue’s high viscosity and sticky nature compound the danger because it adheres to the skin, holding the intense heat against the tissue and quickly causing second-degree burns. A second-degree burn is characterized by blistering.
If hot glue contacts the skin, immediate action is necessary to minimize the injury. The affected area should be held under cool, running water for a minimum of ten to fifteen minutes to draw the heat out of the skin and adhesive. It is important to use cool, not ice-cold, water, as extreme cold can cause further damage to the compromised tissue. The solidified glue should not be forcibly peeled off the skin, as this action can tear or remove the top layers of skin along with the glue, potentially worsening the wound. If the glue is firmly stuck, or if the burn is large or severe, medical attention should be sought immediately after the initial cooling period.