hexabromocyclododecane

Hexabromocyclododecane (HBCD) -chemical formula: C₁₂H₁₈Br₆– is a solid, white odourless powder that is used as a flame retardant additive for thermoplastic polymers. [fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”][1] Hexabromocyclododecane is non-flammable and non-toxic. It melts at around 175 degrees celsius and when heated to temperatures greater than 230 degrees celsius, it breaks down. HBCD does not dissolve in water or some alcohols, but will dissolve in most other organic (carbon-containing) solvents. [2] HBCD consists of twelve carbon, eighteen hydrogen, and six bromine atoms tied to the ring. Because it has 16 possible stereoisomers with different biological activities, the substance poses a difficult problem for manufacture and regulation. The HBCD technical mixture is composed of three main diastereomers denoted as alpha (α), beta (β) and gamma (γ) with traces of others. [3]

Uses [1]

Hexabromocyclododecane’s primary application is in extruded (XPS) and expanded (EPS) polystyrene foam that is used as thermal insulation in the building industry. HBCD is highly efficient in this application so that very low levels are required to reach the desired flame retardancy. Other uses are upholstered furniture, automobile interior textiles, car cushions and insulation blocks in trucks, packaging material, videocassette recorder housing and electric and electronic equipment.

In the Environment [3]

HBCD is ubiquitous in the environment throughout the world and is also found in human tissues, including blood, adipose, and breast milk. When released into the environment, it can travel great distances, bioaccumulating and biomagnifing in the food chain. [4] HBCD can be found in environmental samples such as birds, mammals, fish and other aquatic organisms as well as soil and sediment. On this basis, on 28 October 2008 the European Chemicals Agency decided to include HBCD in the SVHC list, Substances of Very High Concern, within the Registration, Evaluation, Authorisation and Restriction of Chemicals framework. HBCD has been found widely present in biological samples from remote areas and supporting evidences for its classification as Persistent, Bioaccumulative and Toxic (PBT) and undergoes long-range environmental transportation. Since August 2010 Hexabromocyclododecanes are included in the EPA’s List of Chemicals of Concern. [3]

Sources & Routes of Exposure

Sources of Exposure [4]

Consumers using treated products (e.g. automotive upholstery) may be exposed to HBCD that diffuses out of the articles. Estimates of dermal exposure from this source indicate very low exposure and therefore low risk to adults as well as children.
Indirect exposure to HBCD through the environment may occur by consumption of food and drinking water contaminated by HBCD and by inhalation of indoor and outdoor air. Exposure to HBCD from these sources appears to be low and hence low risk is expected.
Toddlers may have the highest exposure to HBCD through ingestion and inhalation of dust/soil containing HBCD released from HBCD containing articles in the house, however, the risk of developing adverse health effects is low. The risk to infants through exposure to HBCD in breast milk is also estimated to be low.
Exposure of workers to HBCD depends on the form of HBCD used, powder or granular forms or aqueous solution, the nature of the work, and the different use patterns.
Workers treating textiles with HBCD products or engaged in the manufacture and cutting of HBCD-treated EPS boards may be exposed to HBCD. The risk to workers of acute adverse health effects such as inhalation toxicity, skin, eye and respiratory irritation and skin sensitisation is low. However, the risk of chronic harmful effects from exposure during these processes is high in a reasonable worst-case scenario.

Routes of Exposure [2]

Hexabromocyclododecane can enter the body either by inhalation of contaminate air, accidental ingestion, or by dermal contact with hexabromocyclododecane.

Health Risks [2,5]

Inhalation of hexabromocyclododecane can cause irritation of the respiratory tract and ingestion may result in gastrointestinal irritation. Dermal contact with hexabromocyclododecane can cause skin irritation. The full effect of hexabromocyclododecane on human health has not been determined. The International Agency for Research on Cancer has not designated hexabromocyclododecane in terms of its carcinogenicity. However, exposure to hexabromocyclododecane at normal background levels is unlikely to have any adverse effect on human health. Recent studies have linked exposure to hexabromocyclododecane with reproductive, developmental, and neurological effects in humans, with a potentially higher impact on children because of their smaller size.

Safety [6]

First Aid Measures

Eye Contact: Check for and remove any contact lenses. In case of contact, immediately flush eyes with plenty of water for at least 15 minutes. Get medical attention.
Skin Contact: In case of contact, immediately flush skin with plenty of water. Remove contaminated clothing and shoes. Wash clothing before reuse. Thoroughly clean shoes before reuse. Get medical attention.
Inhalation: If the victim is not breathing, perform mouth-to-mouth resuscitation. Loosen tight clothing such as a collar, tie, belt or waistband. If breathing is difficult, oxygen can be administered. Seek medical attention if respiration problems do not improve.
Ingestion: Induce vomiting by sticking finger in throat. Lower the head so that the vomit will not re-enter the mouth and throat. Loosen tight clothing such as a collar, tie, belt or waistband. If the victim is not breathing, perform mouth-to-mouth resuscitation. Examine the lips and mouth to ascertain whether the tissues are damaged, a possible indication that the toxic material was ingested; the absence of such signs, however, is not conclusive.

Exposure Controls & Personal Protective Equipment

Engineering Controls

Use process enclosures, local exhaust ventilation, or other engineering controls to keep airborne levels below recommended exposure limits.
If user operations generate dust, fume or mist, use ventilation to keep exposure to airborne contaminants below the exposure limit.

Personal Protective Equipment

The following personal protective equipment is recommended when handling Hexabromocyclododecane:

Splash goggles;
Lab coat;
Dust respirator;
Boots;
Gloves;
Suggested protective clothing might not be sufficient; consult a specialist BEFORE handling this product.
Be sure to use a MSHA/NIOSH approved respirator or equivalent.

Regulation

United States [7]

No occupational exposure limits established.

Australia [8]

No occupational exposure limits established.

References

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