Hydrogen bromide (HBr) is a colourless or sometimes faint yellow gas. It has a sharp, irritating smell and is highly toxic. It can also exist as a liquid — either as hydrobromic acid (HBr dissolved in water) or as a compressed gas under pressure (anhydrous hydrogen bromide).
This substance is extremely dangerous and can cause serious health effects or even death. Hydrogen bromide reacts violently with some chemicals, metals, or water, releasing a flammable and explosive gas. Indoors, it can quickly reach harmful levels. Since the gas is heavier than air, it can settle in low-lying or enclosed spaces. Heating its containers may cause them to explode.
What is Hydrogen Bromide used for?
Hydrogen bromide is man-made and doesn’t occur naturally. It’s used as a reagent and catalyst in many organic chemical reactions. You’ll also find it used in:
The production of inorganic bromides
Cracking petroleum products
Making chemicals and drugs
As a solvent
As a veterinary medicine
Hydrogen Bromide is used as a veterinary medicine.
Sources and Routes of Exposure
Exposure usually happens in workplaces where hydrogen bromide is produced or used. Activities like heating, pouring, spraying, spills, and evaporation can increase the risk of exposure.
The general public is unlikely to come into contact with hydrogen bromide, but it can happen by:
Breathing in contaminated air
Drinking contaminated water near facilities that use or store hydrogen bromide
Skin or eye contact
Eating contaminated food
Common workplace activities that may involve exposure:
Manufacturing or transporting hydrogen bromide
Making inorganic bromides for photography, pharmaceuticals, drying, textiles, engraving, lithography, fire retardants, and other chemical processes
Making brominated fluorocarbons used in fire extinguishers, refrigeration, and aerosols
Organic synthesis—used to make barbiturates, synthetic hormones, and in processes like alkylation (e.g. in the petroleum industry), oxidation, isomerisation, and polymerisation
Analytical chemistry—as a reagent
Etching materials like germanium crystals, silicon disks, and metal alloys
As a solvent for extracting ore minerals
Health Effects
Acute Effects
Exposure to hydrogen bromide can cause immediate health problems:
Skin contact with the liquid can lead to redness, pain, frostbite, and blisters.
Skin exposure to the gas may cause severe burns.
Eye contact with the liquid may cause redness, pain, serious burns, and possibly permanent eye damage.
Breathing in the gas can cause:
Irritation to the nose and throat
Watery eyes
Nosebleeds
Nausea and vomiting
Chest pain or feeling lightheaded
In more serious cases, within hours of breathing the gas, it can irritate the lungs, leading to coughing and shortness of breath.
High-level exposure can result in:
Swelling and spasms in the airways
Fluid buildup in the lungs (pulmonary oedema)
Trouble breathing, low blood pressure, fast heartbeat
Kidney failure, coma, and even death
Swallowing hydrogen bromide can cause severe burns in the mouth and stomach.
Chronic Effects
Long-term or repeated exposure can lead to:
Ongoing irritation of the nose and lungs, causing nasal discharge, coughing, shortness of breath, and bronchitis
Symptoms can be worse for smokers
Safety
First Aid Measures
Eyes: Rinse thoroughly with a large amount of water.
Skin (liquid contact): Soak the area in warm water before removing clothing. Then wash with lots of water.
Skin (gas contact): Take off contaminated clothing and wash the area with lots of water. Remove any jewellery to prevent skin damage from reactions with metal. Bag the clothing in sealed containers for proper disposal.
Inhalation: Move the person to fresh air. Keep them warm and resting. They may need oxygen or other medical help.
Ingestion: Rinse mouth with plenty of water. Do not induce vomiting. Keep the person warm and resting.
Handling and Storage
Handling
Remove contaminated clothing immediately.
Make sure anyone cleaning the clothes knows about the danger of irritation and burns.
Anyone working with hydrogen bromide should wash their hands, arms, and face before:
Eating
Smoking
Using the toilet
Applying cosmetics or medicine
Avoid eating, drinking, smoking, or applying cosmetics in areas where hydrogen bromide is used or stored.
Storage
Store in a cool, dry, and well-ventilated area.
Use tightly sealed containers, and label them according to OSHA standards.
Store in pressurised steel containers.
Keep away from:
Strong oxidisers
Ammonia
Strong bases (caustics)
Fluorine and ozone
Metals like copper, brass, and zinc
Moisture
Exposure Control & Personal Protection
To safely work with hydrogen bromide, use the following precautions:
Ventilation: Ensure good general and local exhaust ventilation to keep the air safe.
Eye and face protection: Wear safety glasses.
Skin protection: Use impervious gloves, coveralls, boots, or other protective clothing.
Respiratory protection: If there’s a risk of leakage, use a self-contained breathing apparatus.
Other equipment: Wear safety shoes when moving or handling gas cylinders.
Regulation
United States
OSHA: The United States Occupational Safety & Health Administration has set the following Permissible Exposure Limit (PEL) for hydrogen bromide of:
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
Australia
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.
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