Acid soldering flux is a chemical used to clean and protect the area where two pieces of metal are joined together. Flux poisoning occurs when someone swallows this substance.
This article is for information only. DO NOT use it to treat or manage an actual poison exposure. If you or someone you are with has an exposure, call your local emergency number (such as 911), or your local poison center can be reached directly by calling the national toll-free Poison Help hotline (1-800-222-1222) from anywhere in the United States.
The harmful substances in soldering fluxes are called hydrocarbons. They include:
- Ammonium chloride
- Hydrochloric acid
- Zinc chloride
Soldering flux contains the above substances.
Other products may also contain fluxes.
Below are symptoms of flux poisoning in different parts of the body.
EYES, EARS, NOSE, AND THROAT
- Loss of vision
- Severe pain in the throat
- Severe pain or burning in the nose, eyes, ears, lips, or tongue
KIDNEYS AND BLADDER
- Decreased urine output
- Kidney failure
STOMACH AND INTESTINES
- Blood in the stool
- Burns of the food pipe (esophagus)
- Severe abdominal pain
- Nausea and vomiting
- Vomiting blood
HEART AND BLOOD VESSELS
- Irregular heart beat
- Low blood pressure that develops rapidly (shock)
LUNGS AND AIRWAYS
- Breathing difficulty (from breathing in the chemical)
- Throat swelling (which may also cause breathing difficulty)
- Holes in the skin or tissues under the skin
Get medical help right away. DO NOT make the person throw up unless poison control or a health care provider tells you to. If the flux is on the skin or in the eyes, flush with lots of water for at least 15 minutes.
If the person swallowed the flux, give them water or milk right away, if a provider tells you to do so. DO NOT give anything to drink if the person has symptoms that make it hard to swallow. These include vomiting, seizures, or a decreased level of alertness. If the person breathed in fumes of the flux, move them to fresh air right away.
Before Calling Emergency
Have this information ready:
- Person's age, weight, and condition
- Name of the product (and ingredients, if known)
- Time it was swallowed
- Amount swallowed
Your local poison control center can be reached directly by calling the national toll-free Poison Help hotline (1-800-222-1222) from anywhere in the United States. This national hotline number will let you talk to experts in poisoning. They will give you further instructions.
This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.
What to Expect at the Emergency Room
Take the container with you to the hospital, if possible.
The provider will measure and monitor the person's vital signs, including temperature, pulse, breathing rate, and blood pressure.
Tests that may be done include:
- Bronchoscopy -- camera down the throat to look for burns in the airways and lungs
- Chest x-ray
- ECG (electrocardiogram or heart tracing)
- Endoscopy -- camera down the throat to look for burns in the esophagus and the stomach
Treatment may include:
- Fluids through the vein (by IV)
- Medicine to treat symptoms
- Tube through the mouth into the stomach to wash out the stomach (gastric lavage)
- Washing of the skin (irrigation), perhaps every few hours for several days
- Surgery to remove burned skin
- Breathing support, including tube through the mouth into the lungs and connected to a breathing machine (ventilator)
How well someone does depends on how severe their poisoning is and how quickly treatment is received. The faster medical help is given, the better the chance for recovery. Damage can continue to occur for several weeks after swallowing soldering flux.
Swallowing such poisons can have severe effects on many parts of the body. Burns in the airway or gastrointestinal tract can lead to tissue necrosis, resulting in infection, shock, and death, even several months after the substance was first swallowed. Scars may form in these tissues, leading to long-term difficulties with breathing, swallowing, and digestion.
Fluxes; Flux poisoning
Aronson JK. Organic solvents. In: Aronson JK, ed. Meyler's Side Effects of Drugs. 16th ed. Waltham, MA: Elsevier; 2016:385-389.
Hoyte C. Caustics. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 148.
Wang GS, Buchanan JA. Hydrocarbons. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 152.
Review Date 9/28/2019
Updated by: Jacob L. Heller, MD, MHA, Emergency Medicine, Emeritus, Virginia Mason Medical Center, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.