What Is Nitric Acid?
The New Jersey Department of Health describes nitric acid as a colorless to yellow liquid with a characteristic, irritating odor, and fuming nitric acid as a reddish, fuming liquid, and says it is used to make fertilizer and for dissolving, etching and cleaning metals. NIOSH notes that fuming nitric acid is concentrated nitric acid that contains dissolved nitrogen dioxide.
Lung effects can be delayed. The NIOSH Pocket Guide lists symptoms including irritation of the eyes, skin and mucous membranes, delayed pulmonary edema, pneumonitis, bronchitis and dental erosion. The New Jersey Department of Health recommends medical observation for 24 to 48 hours after overexposure to nitric acid, as pulmonary edema may be delayed, and gives the same advice after breathing overexposure to nitrogen dioxide.
The New Jersey Department of Health warns that nitric acid reacts violently or explosively with most metals and powdered metals to form flammable and explosive hydrogen gas, and may react violently or cause fires with combustibles and organic materials. It lists the OSHA permissible exposure limit as 2 ppm averaged over an 8-hour workshift, and the NIOSH recommended limit as 2 ppm averaged over a 10-hour workshift, with 4 ppm not to be exceeded during any 15-minute period.
Sources checked September 15, 2026. Every point below links the page it came from.
The sources behind this answer
- Medical referenceThe New Jersey Department of Health says nitric acid is a colorless to yellow liquid used to make fertilizer and to dissolve, etch and clean metals. New Jersey Department of Health ↗
- Medical referenceNIOSH notes that fuming nitric acid is concentrated nitric acid that contains dissolved nitrogen dioxide. NIOSH, CDC ↗
- Government sourceThe NIOSH Pocket Guide lists nitric acid symptoms including eye and skin irritation, delayed pulmonary edema, pneumonitis, bronchitis and dental erosion. NIOSH, CDC ↗
- Government sourceThe New Jersey Department of Health recommends 24 to 48 hours of medical observation after nitric acid overexposure because pulmonary edema may be delayed. New Jersey Department of Health ↗
- Government sourceThe New Jersey Department of Health recommends 24 to 48 hours of observation after breathing too much nitrogen dioxide, as pulmonary edema may be delayed. New Jersey Department of Health ↗
- Government sourceThe New Jersey Department of Health says nitric acid reacts violently with most metals to form flammable hydrogen gas and may cause fires with organic materials. New Jersey Department of Health ↗
- Regulatory filingThe New Jersey Department of Health lists OSHA and NIOSH limits for nitric acid of 2 ppm, with a NIOSH 15-minute limit of 4 ppm. 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.