How can sulfur trioxide and sulfuric acid affect my health?

To protect the public from the harmful effects of toxic chemicals and to find ways to treat people who have been harmed, scientists use many tests.

One way to see if a chemical will hurt people is to learn how the chemical is absorbed, used, and released by the body; for some chemicals, animal testing may be necessary. Animal testing may also be used to identify health effects such as cancer or birth defects. Without laboratory animals, scientists would lose a basic method to get information needed to make wise decisions to protect public health. Scientists have the responsibility to treat research animals with care and compassion. Laws today protect the welfare of research animals, and scientists must comply with strict animal care guidelines.

Sulfuric acid and other acids are very corrosive and irritating and cause direct local effects on the skin, eyes, and respiratory and gastrointestinal tracts when there is direct exposure to sufficient concentrations. Breathing sulfuric acid mists can result in tooth erosion and respiratory tract irritation. Drinking concentrated sulfuric acid can burn your mouth and throat, and it can erode a hole in your stomach; it has also resulted in death. If you touch sulfuric acid, it will burn your skin. If you get sulfuric acid in your eyes, it will burn your eyes and cause them to water. The term "burn" used in these sections refers to a chemical burn, not a physical burn resulting from contacting a hot object. People have been blinded by sulfuric acid when it was thrown in their faces.

Breathing small droplets of sulfuric acid at levels that might be in the air on a day with high air pollution may make it more difficult to breathe. This effect is more likely to occur if you have been exercising or if you have asthma. This effect may also be more likely to occur in children than adults. Breathing sulfuric acid droplets may affect the ability of your respiratory tract to remove other small particles that you have inhaled. If you breathe sulfur trioxide, it turns into sulfuric acid in your upper respiratory tract, and the effects you may experience will be similar to those of sulfuric acid inhalation.

Studies in people who breathed high concentrations of sulfuric acid at work have shown an increase in cancers of the larynx. However, most of the cancers were in smokers who were also exposed to other acids and other chemicals. There is no information that exposure to sulfuric acid by itself is carcinogenic. The carcinogenicity of sulfuric acid has not been studied in animals. The EPA and the U.S. Department of Health and Human Services (DHHS) have not classified sulfur trioxide or sulfuric acid for carcinogenic effects. Based on very limited human data, the International Agency for Research on Cancer (IARC) believes that evidence is sufficient to state that occupational exposure to strong inorganic acid mists containing sulfuric acid is carcinogenic to humans. IARC has not classified pure sulfuric acid for its carcinogenic effects.