What Is Hydrogen Chloride?
ATSDR says that at room temperature, hydrogen chloride is a colorless to slightly yellow, corrosive, nonflammable gas that is heavier than air and has a strong irritating odor. It says hydrogen chloride can be formed during the burning of many plastics, that on contact with water it forms hydrochloric acid, and that both hydrogen chloride and hydrochloric acid are corrosive. ATSDR also says soldering materials often contain hydrogen chloride, so you may be exposed when using them.
ATSDR says hydrogen chloride is irritating and corrosive to any tissue it contacts, that brief exposure to low levels causes throat irritation, and that exposure to higher levels can result in rapid breathing, narrowing of the airways, blue coloring of the skin, accumulation of fluid in the lungs and even death. It says some people may develop reactive airways dysfunction syndrome (RADS), a type of asthma caused by some irritating or corrosive substances.
The New Jersey Department of Health recommends medical observation for 24 to 48 hours after overexposure, as pulmonary edema may be delayed, and lists both the OSHA permissible exposure limit and the NIOSH recommended limit for hydrogen chloride as 5 ppm, not to be exceeded at any time.
Sources checked September 15, 2026. Every point below links the page it came from.
The sources behind this answer
- Medical referenceATSDR says hydrogen chloride is a colorless to slightly yellow, corrosive, nonflammable gas that is heavier than air with a strong irritating odor. ATSDR, CDC ↗
- Government sourceATSDR says hydrogen chloride can form when many plastics burn, and forms corrosive hydrochloric acid on contact with water. ATSDR, CDC ↗
- Government sourceATSDR says brief low-level hydrogen chloride exposure irritates the throat, and higher levels can cause fluid in the lungs and even death. ATSDR, CDC ↗
- Government sourceATSDR says some people develop reactive airways dysfunction syndrome, a type of asthma, after hydrogen chloride exposure. ATSDR, CDC ↗
- Government sourceATSDR says soldering materials often contain hydrogen chloride, so people may be exposed when soldering. ATSDR, CDC ↗
- Regulatory filingThe New Jersey Department of Health lists both OSHA and NIOSH limits for hydrogen chloride as 5 ppm, not to be exceeded at any time. New Jersey Department of Health ↗
- Government sourceThe New Jersey Department of Health recommends 24 to 48 hours of medical observation after hydrogen chloride overexposure because pulmonary edema may be delayed. New Jersey Department of Health ↗
Sources checked September 15, 2026. A brand statement is the company’s own claim, which we report but have not verified. Our grades are model-based estimates, not lab tests.