What Is Sulfuric Acid Vapor?

Sulfuric acid vapor is sulfuric acid (H₂SO₄) that is in a gaseous state but is low enough in temperature that it can be condensed into liquid by changes in pressure without a change in temperature. People can be exposed to dangerous levels of vapor as a result of things such as working at an industrial site where sulfuric acid is used and coming into contact with ruptured automobile batteries and laboratory accidents. Sulfuric acid is highly corrosive, and exposure to its vapor is a serious health hazard. Victims should should be removed from the source of the vapor, taken into fresh air, and provided with medical attention as quickly as possible.

Especially dangerous to living beings, sulfuric acid is very reactive with water and produces a great deal of heat while reacting with it in addition to being corrosive enough to burn human skin and flesh. Consequently, the damage caused by the initial corrosive effects is compounded by additional damage from intense heat during exposure and the subsequent dehydration of damaged tissues. Under United States labor workplace regulations, the legal limit for workplace levels of sulfuric acid vapor levels in the air is 1 milligram of acid per cubic meter. The American Conference of Governmental Industrial Hygienists, an organization that produces widely used guidelines for safe chemical exposure, also gives a maximum safe limit for extended workplace exposure of milligrams per cubic meter as well as a maximum safe short-term exposure of 3 milligrams per cubic meter.

If inhaled, sulfuric acid vapor can cause serious chemical burns to the inside of the mouth, nose, and respiratory tract, resulting in pain and difficulty breathing. It can also cause a buildup of fluid, called edema, in the lungs, bronchi, or larynx; chemical pneumonitis, or inflammation of the lungs; and lung spasms. These symptoms can be fatal if they impair breathing enough to cause respiratory failure.

Even when not inhaled, the vapor is dangerous. Contact with the skin can cause painful blistering, burns, and necrosis. Coming in contact with the eyes can cause irritation, burning, or blurred vision, and if severe enough, can cause permanent damage to the victim's sense of sight.

In addition to the damage from a single incident of concentrated exposure, repeated exposure to low levels of sulfuric acid vapor over time can cause chronic skin, eye, and respiratory inflammation. If inhaled or exhaled through the mouth, it can also cause dental erosion. Frequent low-level exposure to sulfuric acid vapors is also associated with an increased risk of cancer in the lungs and respiratory tract.