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Nitric acid SDS in short: nitric acid (CAS 7697-37-2) is a corrosive, oxidizing, toxic-by-inhalation acid, and what the safety data sheet (SDS) says about it depends on concentration. Under EU CLP, nitric acid above 70% carries H272, H314 and H330; at 70% or below, H331 replaces H330. The occupational limit is 2 ppm as an 8-hour average (OSHA PEL and NIOSH REL), and storage is built around keeping it away from combustibles, metals, alkalies and organics. This page puts those points in one place so you can check a manufacturer SDS against them.
What an SDS covers for nitric acid
A manufacturer SDS is written for one product, in one concentration, from one supplier. That is why the search results for this topic are individual PDFs for 10%, 0.5 N, 6 M, 30% or 51-64% solutions. The 16-section layout is the same every time, but for nitric acid these sections deserve the closest read:
- Section 2 (hazard identification): the signal word, pictograms and H and P statements. Compare them with the concentration table below.
- Section 3 (composition): the stated concentration, which decides which classification applies.
- Section 4 (first-aid measures): compare with the NIOSH first-aid summary below.
- Section 7 (handling and storage) and section 10 (stability and reactivity): incompatibilities and storage conditions.
- Section 8 (exposure controls and personal protection): exposure limits, eyewash and respirator guidance.
- Sections 13 and 14 (disposal and transport): follow the supplier’s wording and your institution’s waste procedures; this page does not substitute for them.
For the same walk-through applied to other solvents, see the CASRAI guides on the acetone SDS and the methanol SDS.
GHS classification by concentration
The information that single-product SDS pages do not give is how the classification moves with concentration. PubChem’s GHS record for nitric acid (compound CID 944), read 2026-11-08, lists the EU CLP classification in two bands:
| Concentration band | Signal word | Pictograms | Hazard statements |
|---|---|---|---|
| Above 70% | Danger | GHS03, GHS05, GHS06 | H272, H314, H330 |
| 70% or below | Danger | GHS03, GHS05, GHS06 | H272, H314, H331 |
In plain terms: H272 may intensify fire (oxidizer), H314 causes severe skin burns and eye damage, H330 is fatal if inhaled and H331 is toxic if inhaled. The precautionary statements also differ slightly between the bands: the 70%-or-below entry adds P261 and drops P284 and P320.
Two practical consequences follow. First, the SDS for a dilute solution and the SDS for concentrated acid will not look the same, so a colleague’s SDS for a different bottle is not a substitute for yours. Second, PubChem notes that company notifications to ECHA vary: some list only H272 and H314, others add H290 (may be corrosive to metals) or H318 (serious eye damage), because classification depends on concentration and on impurities. If two suppliers’ SDSs for the same nominal strength differ, that variation is expected and the supplier’s own SDS for the product on your shelf is the one to follow.
Exposure limits and health effects
The NIOSH Pocket Guide entry for nitric acid (read 2026-11-08) gives these values:
| Measure | Value |
|---|---|
| OSHA PEL, 8-hour TWA | 2 ppm (5 mg/m3) |
| NIOSH REL, TWA | 2 ppm (5 mg/m3) |
| NIOSH REL, short-term (ST) | 4 ppm (10 mg/m3) |
| IDLH | 25 ppm |
NIOSH lists inhalation, ingestion and skin or eye contact as the exposure routes. The symptoms it records are irritation of the eyes, skin and mucous membranes; delayed pulmonary edema, pneumonitis and bronchitis; and dental erosion. The target organs are the eyes, skin, respiratory system and teeth. The word “delayed” matters for supervisors: an inhalation exposure that feels minor at first is not a reason to skip medical evaluation.
First aid per NIOSH: irrigate the eyes immediately, flush the skin with water immediately, give respiratory support after inhalation, and seek medical attention if the acid is swallowed. This is general reference information, not individual medical advice; follow your institution’s emergency procedure and the SDS section 4 for your product. The wider corrosives context is in the corrosive chemicals guide.
PPE and respirator tiers
NIOSH’s protection notes for nitric acid say to prevent skin and eye contact, remove wet or contaminated clothing, wash the skin, and have an eyewash and a quick-drench facility available (it ties the drench facility to solutions with pH below 2.5). Its respirator tiers for airborne exposure are:
- Up to 25 ppm: a supplied-air respirator in continuous-flow mode (assigned protection factor 25), or a full-facepiece cartridge respirator, gas mask or self-contained breathing apparatus (APF 50).
- Unknown concentrations or IDLH conditions: a pressure-demand SCBA with a full facepiece (APF 10,000).
Glove selection is a separate question that depends on concentration and contact time; the nitrile glove chemical resistance guide explains how breakthrough data is read.
Storage and incompatibilities
NIOSH lists these incompatibilities: combustible materials, metallic powders, hydrogen sulfide, carbides and alcohols. Nitric acid reacts with water to produce heat, is corrosive to metals, and while it does not burn itself it increases the flammability of combustibles.
For storage, the NFPA Fire Protection Guide to Hazardous Materials (14th edition), as quoted in the HSDB record on PubChem, says to store in a cool, dry, well-ventilated location and to separate it from alkalies, metals, organics and other oxidizing materials. The ILO Encyclopedia (1983) entry quoted in the same record adds storage sheltered from sunlight and heat, with provision for neutralization if a leak occurs. The general segregation logic for acids, oxidizers and organics is laid out in the chemical storage compatibility guide.
Common misunderstandings
- “It is just an acid, so store it with the other acids.” Nitric acid is also an oxidizer (H272) and is incompatible with organics and alcohols, so it is the acid most likely to need its own segregation.
- “One SDS covers every bottle.” Classification differs above and below 70%, and suppliers’ notifications differ again.
- “No pain, no problem.” NIOSH records delayed pulmonary effects after inhalation.
- “The SDS is the whole safety program.” It is the supplier’s hazard communication; your institution’s chemical hygiene plan and waste procedures still apply.
FAQ
What are the hazards of nitric acid?
It is corrosive (severe skin burns and eye damage, H314), an oxidizer that may intensify fire (H272), and toxic or fatal by inhalation depending on concentration (H331 at 70% or below, H330 above 70%). Inhalation can cause delayed pulmonary edema.
What is the exposure limit for nitric acid?
Both the OSHA PEL and the NIOSH REL are 2 ppm (5 mg/m3) as a time-weighted average; NIOSH adds a 4 ppm short-term limit and an IDLH of 25 ppm.
What should nitric acid not be stored with?
Per NIOSH and NFPA: combustible materials, metallic powders, hydrogen sulfide, carbides, alcohols, alkalies, metals, organics and other oxidizing materials.
Does the SDS differ between a 10% solution and concentrated acid?
Yes. The CLP classification changes at 70% (H330 versus H331), and the stated concentration in section 3 of each product’s SDS determines what applies.
Sources
- NIOSH Pocket Guide to Chemical Hazards: Nitric acid (CDC), read 2026-11-08.
- PubChem: Nitric acid (CID 944), GHS classification and HSDB storage conditions, read 2026-11-08.
This page is general reference information for laboratory staff and EHS officers. It is not a substitute for the SDS supplied with your product or for your institution’s safety procedures.
