Is Hexabromocyclododecane safe when breathed in?

Inhalation exposure to hexabromocyclododecane (HBCD) presents an unreasonable risk to human health, including developmental effects such as decreased fetal viability and body weight, short-term changes in thyroid hormones that may lead to irreversible developmental outcomes like neurotoxicity, and chronic thyroid disruption.

Why here

HBCD is an additive flame retardant in products like building insulation, textiles, and plastics. It is not chemically bound and can be released as fine dust particles into indoor air, which can then be inhaled.

What would have to be true

Short- and long-term inhalation exposure to HBCD dust and particles released from consumer products and building materials, particularly in occupational settings without personal protective equipment, but also for the general population.

Hexabromocyclododecane (HBCD) is suspected of damaging fertility or the unborn child, may cause harm to breast-fed children, and inhalation of its dust can quickly reach nuisance-causing concentrations.

Why here

HBCD is released as dust from products into indoor air, which can be inhaled by the general population, including pregnant women and children.

What would have to be true

Inhalation of airborne HBCD dust, particularly in indoor settings where HBCD-treated products are present.

Hexabromocyclododecane (HBCD) is classified as a persistent organic pollutant (POP) due to its persistence, bioaccumulation, long-range environmental transport, and toxicity, leading to its ban or restriction in many regions, and presents potential human health concerns based on animal test results indicating potential reproductive, developmental, and neurological effects from exposure, including inhalation.

Why here

As a non-covalently bound additive in various products (insulation, textiles), HBCD can migrate out and become part of indoor dust and air, making inhalation a route of exposure for the general population.

What would have to be true

Inhalation of HBCD-containing indoor dust and airborne particles from products and environmental media.

Studies in rats and zebrafish suggest that hexabromocyclododecane (HBCD) can disrupt the thyroid hormone system, affecting the metabolism, transport, and generation of thyroid hormones.

Why here

HBCD, being an additive flame retardant, can be released as dust from consumer products and building materials into indoor air, leading to inhalation exposure.

What would have to be true

Inhalation exposure to HBCD dust and particles from indoor environments, as observed in animal models.

Animal and in-vitro studies suggest that hexabromocyclododecane (HBCD) can induce developmental neurotoxic effects, alter neurotransmitter uptake, and affect neural signaling, apoptosis, and oxidative stress.

Why here

HBCD, as an additive flame retardant, can be released as dust from consumer products and building materials into indoor air, leading to inhalation exposure.

What would have to be true

Inhalation of HBCD dust and particles from indoor environments, as demonstrated in animal and in-vitro studies.

Hexabromocyclododecane (HBCD) is classified as a persistent organic pollutant (POP) and its production and use are restricted or phased out globally under Annex A of the Stockholm Convention due to its high bioaccumulation, long-distance transport, and associated toxicity.

Why here

HBCD, used as an additive flame retardant in building materials and consumer products, is not chemically bound and can leach into indoor environments, contributing to its persistence and potential for human exposure.

What would have to be true

Presence in indoor air and dust from products like insulation, electronics, and textiles.

Exposure to hexabromocyclododecane (HBCD) is linked to endocrine disruption, specifically affecting the thyroid hormone system in humans and animals.

Why here

HBCD, released from flame-retarded products into indoor air and dust, can be inhaled or ingested, leading to systemic exposure.

What would have to be true

Inhalation of HBCD-containing dust and particles in indoor air, and ingestion of indoor dust, with toddlers having higher estimated intakes from dust ingestion (up to 95% of total intake in worst-case scenarios). Concentrations in indoor air range from <1.6-2 pg/m³ and in dust from 45-340 ng/g.

Hexabromocyclododecane (HBCD) has been shown to induce cancer through a nonmutagenic mechanism in humans, although specific studies on carcinogenicity following inhalation exposure have not been identified.

Why here

HBCD can be released from flame-retarded products into indoor air and dust, leading to human exposure through inhalation of particles and ingestion of dust.

What would have to be true

Exposure to HBCD in indoor environments through dust ingestion and inhalation of airborne particles.

Hexabromocyclododecane (HBCD) is classified as an endocrine disruptor and is associated with developmental toxicity, including detrimental effects on the neuronal, endocrine, cardiovascular, liver, and reproductive systems.

Why here

Children can be exposed to HBCD through ingestion of contaminated indoor dust and food, as HBCD is a flame retardant that can migrate from products into the environment and bioaccumulate.

What would have to be true

Exposure occurs through ingestion of indoor dust (e.g., average 3.2 ng/day, high 8.0 ng/day for adults, with children potentially having higher dust ingestion rates) and food (e.g., average 7.2 ng/day for adults). HBCD has been detected in human serum and breast milk. Risks from acute exposures include developmental effects such as decreased fetal viability and body weight, and short-term changes in thyroid hormones.

HBCD exposure can lead to neurodevelopmental effects, including neurotoxicity and changes in spontaneous behavior, learning, and memory functions.

Why here

Ingestion by children, particularly during sensitive developmental windows, can interfere with cognitive function and behavior.

What would have to be true

Exposure occurs through ingestion of indoor dust and food. Risks from acute exposures include developmental effects such as short-term changes in thyroid hormones, which may result in irreversible developmental outcomes such as neurotoxicity.

Hexabromocyclododecane (HBCD) may cause harm to breast-fed children.

Why here

HBCD has been detected in human breast milk, indicating a potential transfer pathway to infants through ingestion.

What would have to be true

Exposure occurs through breast milk from mothers exposed to HBCD via dust and food ingestion.

Studies suggest HBCD is linked to increased oxidative stress, reactive oxygen species (ROS) production, DNA damage, and increased cell apoptosis.

Why here

Ingested HBCD can induce cellular stress and damage, potentially impacting developing systems in children.

What would have to be true

This is a mechanistic claim, observed in in vitro and animal studies (zebrafish, copepods) at various concentrations (e.g., 0.1-1.0 mg/L in zebrafish embryos).