Hydrogen bromide is the diatomic molecule HBr . It is a colourless, or sometimes faint yellow, highly toxic gas with a sharp, irritating odour. It can also be found as a liquid, either as hydrobromic acid (hydrogen bromide dissolved in water) or as a compressed gas under pressure (anhydrous hydrogen bromide). It is an extremely dangerous substance and must be handled with caution as it can cause severe health effects and death. Hydrogen bromide can react violently when mixed with some chemicals, metals or water, forming a flammable, explosive gas. When hydrogen bromide is released into indoor air, dangerous levels will be reached very quickly. The gas is heavier than air and can travel to lowlying or confined areas. Containers of hydrogen bromide may explode when heated. 
Hydrogen Bromide does not occur naturally it is made by humans in a laboratory. It is a reagent and a catalyst in many organic reactions. Hydrogen Bromide is also used in many inorganic bromides as well as in cracking of petroleum products. It is used to make chemicals and drugs, as a solvent and as a veterinary drug.
Sources and Routes of Exposure [2,4]
Significant exposure usually occurs in the industries where hydrogen bromide is produced or used. Heating, pouring, spraying, spills and evaporation create conditions that increase the risk of employee exposure. Though unlikely, the general population may be exposed by breathing in contaminated air or by drinking contaminated water from a facility using or storing hydrogen bromide, by skin or eye contact with the gas or liquid, or by eating food that has been contaminated with hydrogen bromide .
The following operations may involve hydrogen bromide and lead to worker exposures to this substance:
- The manufacture and transportation of hydrogen bromide
- Use in manufacture of inorganic bromides for use in photography, pharmaceuticals, industrial drying, textile finishing, engraving and lithography, chemical synthesis, and fire retardants
- Use in manufacture of brominated fluorocarbons for fire extinguishing, refrigeration, and aerosols
- Use in organic synthesis as an intermediate (e.g., for barbiturate manufacture and the manufacture of synthetic hormones); as a catalyst for alkylation of aromatic compounds (e.g., in the petroleum industry); controlled oxidations, isomerisation of conjugated diolefins, and polymerisation
- Use as a reagent in analytical chemistry; in the etching of germanium crystals, silicon disks, and metal alloys
- Use as a solvent for ore minerals
Health Risks 
The following acute effects may be noted immediately or shortly after exposure:
- When the skin is exposed to the liquid, redness, pain, frostbite and blisters can occur.
- Severe burns can occur when the skin is exposed to the gas.
- Eye contact with the liquid can cause redness, pain, severe burns and possible permanent eye damage.
- Exposure to hydrogen bromide gas may result in nose and throat irritation, watery eyes, bloody nose, nausea, vomiting, chest pain and/or lightheadedness.
- Immediately or within a few hours after breathing the gas, the lungs can become irritated, causing coughing and/or shortness of breath.
- In addition to the effects listed above, higher exposure can cause swelling and spasms in the airway and a build-up of fluid in the lungs (pulmonary oedema), severe shortness of breath, loss of consciousness, low blood pressure, rapid heartbeat, kidney failure, coma and death.
- Drinking a solution of hydrogen bromide can cause severe burns in the mouth and stomach.
The following chronic health effects can occur after high or repeated exposure and can last for months or years:
- Repeated inhalation can cause nasal discharge and respiratory tract irritation including coughing, shortness of breath and bronchitis.
- Smoking may worsen symptoms of diseases/conditions related to hydrogen bromide exposure.
First Aid Measures 
- Eye contact Flush the affected eye with large amounts of water.
- Skin contact If skin has come into contact with liquid hydrogen bromide, submerge the affected area in warm water prior to removing the clothing. Wash the area with large amounts of water. If the skin has come in contact with hydrogen bromide gas, remove the clothing and wash the area with large amounts of water. Remove any jewellery to prevent skin damage caused by hydrogen bromide contact with metal. If the clothing has been removed, double bag and place the contaminated clothing in closed containers until it can be disposed of properly.
- Breathing Leave the area of the exposure and move to a source of fresh air. Keep the exposed individuals warm and allow them to rest. Professional medical care may be needed to provide oxygen and respiratory assistance.
- Ingestion Rinse the mouth with large amounts of water. Do not induce vomiting. Keep the individual warm and allow them to rest.
Handling and Storage 
Clothing contaminated with hydrogen bromide should be removed immediately, and provisions should be made for the safe removal of the chemical from the clothing. Persons laundering the clothes should be informed of the hazardous properties of hydrogen bromide, particularly its potential for causing irritation and burns. A worker who handles hydrogen bromide should thoroughly wash hands, forearms, and face with soap and water before eating, using tobacco products, using toilet facilities, applying cosmetics, or taking medication. Workers should not eat, drink, use tobacco products, apply cosmetics, or take medication in areas where hydrogen bromide or a solution containing hydrogen bromide is handled, processed, or stored.
Hydrogen bromide should be stored in a cool, dry, well-ventilated area in tightly sealed containers that are labelled in accordance with OSHA’s Hazard Communication Standard [29 CFR 1910.1200]. Store in pressurised steel containers. Containers of hydrogen bromide should be protected from physical damage and should be stored separately from strong oxidisers, ammonia, strong caustics, fluorine, common metals such as copper, brass, and zinc, moisture, fluorine, or ozone.
Exposure Controls and Personal Protection 
- Engineering Controls: Provide adequate general and local exhaust ventilation to maintain concentration below exposure limits.
- Eye and Face Protection: Safety glasses
- Skin Protection: Impervious gloves, coveralls, boots, and/or other resistant protective clothing.
- Respiratory Protection: In case of leakage, use self-contained breathing apparatus.
- Other Protective Equipment: Safety shoes when handling cylinders.
United States 
OSHA: The United States Occupational Safety & Health Administration has set the following Permissible Exposure Limit (PEL) for hydrogen bromide of:
- General Industry: 29 CFR 1910.1000 Table Z-1 – 3 ppm, 10 mg/m3 TWA;
- Construction Industry: 29 CFR 1926.55 Appendix A – 3 ppm, 10 mg/m3 TWA
- Maritime: 29 CFR 1915.1000 Table Z-Shipyards – 3 ppm, 10 mg/m3 TWA
ACGIH: The American Conference of Governmental Industrial Hygienists has set a Threshold Limit Value (TLV) of 2 ppm, 6.6 mg/m3 Ceiling.
NIOSH: The National Institute for Occupational Safety and Health has set a Recommended Exposure Limit (REL)of 3 ppm, 10 mg/m3 Ceiling
Safe Work Australia: Safe Work Australia has set a Time Weighted Average (TWA) concentration for hydrogen bromide of 3ppm or 9.9mg/m3 for a 40-hour work week.