Safety data reference
Sodium Hypochlorite Solution 12.5% — Safety Data Summary
- CAS7681-52-9
- EC231-668-3
- FormulaNaOCl
- MW74.44 g/mol
Read this before you use this page
This is a general reference summary for Sodium Hypochlorite Solution 12.5%, compiled from publicly published authoritative sources — PubChem, the NIOSH Pocket Guide, ILO/WHO International Chemical Safety Cards, CAMEO Chemicals, the ECHA C&L Inventory, OSHA and the eCFR. Every figure on this page is traceable to one of the sources listed at the foot of the page.
It is not a supplier safety data sheet and must not be used as one. A compliant SDS is batch-specific and manufacturer-specific: it carries the actual supplier identity, emergency contact, product identifier, grade, impurity profile and the classification that follows from them. Before you accept, store, handle or ship any consignment, obtain the manufacturer’s own signed SDS for that grade and lot.
01Hazard identification
Classification: Skin corrosion, Category 1B · Serious eye damage, Category 1 · Hazardous to the aquatic environment, Acute 1 (M=10) and Chronic 1 — EU harmonised
Pictograms: GHS05 Corrosion · GHS09 Environment
- H314 Causes severe skin burns and eye damage.
- H318 Causes serious eye damage.
- H400 Very toxic to aquatic life.
- H410 Very toxic to aquatic life with long lasting effects.
- H290 May be corrosive to metals. (Widely self-classified)
- H335 May cause respiratory irritation. (Widely self-classified)
Identification
| IUPAC name | sodium hypochlorite |
|---|---|
| Synonyms | Sodium oxychloride, bleach, liquid bleach, chlorine bleach, soda bleach liquor, Javelle water, antiformin |
| CAS number | 7681-52-9 |
| EC number | 231-668-3 |
| Molecular formula | NaOCl |
| Molecular weight | 74.44 g/mol |
02Precautionary statements
Prevention
- P260 Do not breathe dust, fume, gas, mist, vapours or spray.
- P264 Wash hands thoroughly after handling.
- P273 Avoid release to the environment.
- P280 Wear protective gloves, protective clothing, eye protection and face protection.
- P234 Keep only in the original container.
Response
- P301+P330+P331 IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.
- P302+P361+P354 IF ON SKIN: Take off immediately all contaminated clothing. Immediately rinse with water for several minutes.
- P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
- P305+P354+P338 IF IN EYES: Immediately rinse with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing.
- P316 Get emergency medical help immediately.
- P363 Wash contaminated clothing before reuse.
- P391 Collect spillage.
Storage
- P403+P233 Store in a well-ventilated place. Keep container tightly closed.
- P405 Store locked up.
- P406 Store in a corrosion-resistant container with a resistant inner liner.
Disposal
- P501 Dispose of contents and container in accordance with local, regional and national regulations.
03Physical and chemical properties
| Appearance | Clear, colourless to slightly yellow or greenish-yellow watery liquid |
|---|---|
| Odour | Characteristic household-bleach or chlorine odour; disagreeable and sweetish |
| Odour threshold | Estimated equal to chlorine, approximately 0.3 ppm |
| pH | Approximately 13 for solutions above 10% active chlorine |
| Melting point | −30 to −20 °C (solution) |
| Boiling point | 111 °C (in solution) |
| Flash point | Not applicable — non-combustible aqueous solution |
| Flammability | Non-combustible, but a strong oxidant that reacts violently with combustible and reducing materials |
| Vapour pressure | 2–2.5 kPa at 20 °C |
| Relative density | 1.20–1.25 g/mL at 20 °C |
| Water solubility | Miscible; 293 g/L NaOCl at 20 °C |
| log Kow | Not applicable — ionic inorganic salt |
| Active chlorine | 12.5% w/w NaOCl corresponds to roughly 11.9% available chlorine |
| Decomposition temp. | Releases chlorine above 35 °C; decomposes on heating, on contact with acids and under light |
04Exposure controls and occupational limits
| OSHA PEL | None established |
|---|---|
| NIOSH REL | None established — no NIOSH Pocket Guide entry exists |
| ACGIH TLV | None established |
| NIOSH IDLH | None established |
| AIHA WEEL | STEL 2 mg/m3, 15 minutes |
| Governing airborne hazard | Chlorine gas released on acidification or heating. Chlorine: OSHA PEL ceiling 1 ppm; NIOSH REL ceiling 0.5 ppm (15 min); ACGIH TLV 0.1 ppm TWA, 0.4 ppm STEL; IDLH 10 ppm |
05First-aid measures
- Inhalation
- Fresh air, rest, half-upright position. Artificial respiration and oxygen may be needed. Refer immediately for medical attention. Symptoms of pulmonary oedema may be delayed. Do NOT perform mouth-to-mouth resuscitation.
- Skin contact
- Rinse first with plenty of water for at least 15 minutes, then remove contaminated clothes and rinse again. Refer immediately for medical attention.
- Eye contact
- Rinse with plenty of water for several minutes, removing contact lenses if easily possible. Refer immediately for medical attention.
- Ingestion
- Rinse mouth. Do NOT induce vomiting. Give one or two glasses of water to drink. Refer immediately for medical attention.
06Fire-fighting measures
- Suitable extinguishing media
- Use the agent appropriate to the surrounding fire. Dry chemical, CO2, foam, or water in flooding quantities or water fog. Keep drums and containers cool by spraying with water.
- Unsuitable media
- Amines, which may produce explosive chloramines, and oxidisable materials such as oxalic acid.
- Specific hazards
- The material itself does not burn but is a strong oxidiser and may support combustion. Decomposes on heating and on contact with acids, generating chlorine gas and oxygen. Contact with urea forms explosive nitrogen trichloride. Reacts with sulfuric acid producing heat and chlorine. Containers may rupture from oxygen evolution.
- Protective equipment
- Positive-pressure SCBA with full facepiece plus chemical protective clothing, rubber gloves, goggles, plastic coveralls and boots. Apply water from as far a distance as possible.
- ERG guide
- Guide 154 (Substances — toxic and/or corrosive, non-combustible)
07Accidental release measures
- Personal precautions
- Complete protective clothing including self-contained breathing apparatus. Ventilate. Keep unauthorised personnel away and stay upwind, uphill and upstream. Eliminate ignition sources.
- Environmental precautions
- Do NOT let the chemical enter the environment. It is very toxic to aquatic life with long lasting effects. Prevent entry into waterways, sewers, basements or confined areas.
- Containment and clean-up
- Collect leaking and spilled liquid in sealable NON-METALLIC containers as far as possible, then wash away the remainder with plenty of water. Do NOT absorb in sawdust or other combustible absorbents. For land spills, dike and contain, absorb bulk liquid with fly ash or cement powder, then neutralise with agricultural lime, crushed limestone or sodium bicarbonate. Sodium thiosulfate or sodium disulfite are the chemical neutralisers.
- ERG isolation distances
- Isolate the spill or leak area in all directions for at least 50 m (150 ft). Fire involving a tank: isolate and consider evacuation for 800 m (half a mile).
08Handling and storage
- Safe handling
- Use with adequate ventilation. Avoid contact with skin and eyes and avoid breathing mist or released chlorine. Never mix with acids, which releases chlorine; with ammonia or ammonium salts, which forms chloramines and nitrogen trichloride; or with other cleaning products. Use non-metallic transfer equipment. Vent caps must be checked with full personal protection.
- Safe storage
- Keep cool — store at 15–18 °C and not above 20 °C. Keep in the dark, out of direct sunlight. Store well closed in original vented containers only, because oxygen evolution requires venting. Separate from combustible substances, reducing agents, acids, and food and feedstuffs.
- Incompatible materials
- All acids; ammonia, ammonium salts and urea; amines, which form explosive chloramines; ethyleneimine; combustible and reducing materials; oxidisable organics. Attacks copper and its compounds and light metals including aluminium, and most metals generally. Avoid sunlight, UV and heat.
09Stability and reactivity
- Reactivity
- Strong oxidising agent, normally supplied and used only in solution. The aqueous solution is a strong base and corrosive.
- Chemical stability
- Inherently unstable. Decomposes over time releasing oxygen, and is unstable in air unless stabilised with excess sodium hydroxide. Stability improves at high pH and low temperature and degrades rapidly at pH 5–6, on heating and on light exposure. At 24 °C, available chlorine fell below 50% of the original after two years.
- Hazardous reactions
- Contact with acids liberates chlorine gas. With urea it forms nitrogen trichloride, which explodes spontaneously in air — documented explosions have occurred where hypochlorite met ammonium-salt residues in effluent drains and in a tank cleaned without an intermediate rinse. With primary amines it forms explosive chloramines. Reacts violently with combustible and reducing materials.
- Conditions to avoid
- Heat above 35 °C, direct sunlight and UV, contact with acids, contact with ammonia, amines or urea, contamination with metals, and drying to the anhydrous solid, which is very explosive.
- Decomposition products
- Chlorine gas; oxygen; hydrogen chloride; sodium oxide on thermal decomposition; chloramines and nitrogen trichloride in the presence of nitrogen compounds.
10Toxicological information
| LD50 oral, rat | 8,910 mg/kg. EU biocide assessment: > 2,000 mg available chlorine/kg bw |
|---|---|
| LD50 dermal, rabbit | > 2,000 mg available chlorine/kg bw |
| LC50 inhalation, rat | > 10.5 mg available chlorine/L, 1-hour exposure |
| Routes of exposure | Inhalation of aerosol and released chlorine, ingestion, skin contact, eye contact. Serious local effects by all routes |
| Symptoms | Corrosive to the eyes, skin, respiratory tract and digestive organs. Inhalation: burning sensation, cough, laboured breathing, shortness of breath, sore throat, with a risk of delayed-onset lung oedema. Skin: redness, pain, burns, blisters. Eye: redness, pain, severe burns. Ingestion: burning sensation, abdominal pain, vomiting, shock or collapse |
| Long-term | Repeated or prolonged skin contact may cause dermatitis |
| Target organs | Eyes, skin, respiratory tract, gastrointestinal tract |
| IARC | Group 3 — not classifiable, evaluated as hypochlorite salts |
| NTP | Not listed in the Report on Carcinogens |
| OSHA | Not regulated as a carcinogen |
11Ecological information
| LC50 fish (96 h) | Rainbow trout 4.18 mg/L; bluegill sunfish 4.3 mg/L; sheepshead minnow 0.38 mg/L; tidewater silverside 0.054 mg/L |
|---|---|
| EC50 Daphnia magna (48 h) | 1.7 mg/L; other reported values 0.040–2.3 mg/L. Mysid shrimp 96 h LC50 0.16 mg/L |
| CLP consequence | Aquatic Acute 1 with M-factor 10; Aquatic Chronic 1 with M-factor 1 |
| Biodegradability | Not applicable in the organic sense. Active chlorine degrades rapidly by reaction with organic matter — DT50 in surface water 56 minutes |
| Bioaccumulation | Negligible — ionic, highly water-soluble and rapidly degraded |
| Mobility in soil | Highly mobile as hypochlorite or chloride ion, but persistence is very short because it reacts rapidly with soil organic matter |
12Transport information
| UN number | UN 1791 |
|---|---|
| Proper shipping name | Hypochlorite solutions |
| Transport hazard class | 8 — Corrosive |
| Packing group | II or III — assigned by measured corrosivity. PG II normally applies to a 12.5% commercial solution |
| Marine pollutant | YES — listed in 49 CFR 172.101 Appendix B. Not a severe marine pollutant |
| ERG guide | 154 |
| Air freight limits | PG II: 1 L passenger, 30 L cargo. PG III: 5 L passenger, 60 L cargo |
| Additional | Environmentally hazardous substance mark applies. Do not transport with food and feedstuffs |
13Regulatory information
| TSCA | Listed as hypochlorous acid, sodium salt (1:1); subject to Chemical Data Reporting |
|---|---|
| SARA 313 (TRI) | Not listed in 40 CFR 372.65. Note that chlorine is TRI-listed, but that does not extend to hypochlorite |
| California Prop 65 | Not listed |
| EU REACH | Registered; CLP Annex VI harmonised entry Index 017-011-00-1. Approved active substance under the Biocidal Products Regulation |
| CERCLA RQ | 100 lb (45.4 kg) — 40 CFR 302.4 |
| Clean Water Act | Designated hazardous substance under CWA §311 |
| RCRA | No listed waste code. Waste may be characteristically hazardous as D002 (corrosivity) if pH is 12.5 or above |
| FIFRA | Registered antimicrobial pesticide, EPA Pesticide Chemical Code 014703 |
Frequently asked questions
Why must sodium hypochlorite never be mixed with acid?
Acidifying hypochlorite drives the equilibrium towards hypochlorous acid and then to chlorine gas, which is released immediately and in quantity. Chlorine has a NIOSH ceiling of 0.5 ppm and an IDLH of 10 ppm, so a small drain-level mixing accident in a confined space can reach dangerous concentrations within seconds.
Is sodium hypochlorite a marine pollutant?
Yes. Both “Hypochlorite solutions” and “Sodium hypochlorite solution” appear in the 49 CFR 172.101 Appendix B list of marine pollutants, so the environmentally hazardous substance mark and the words “Marine Pollutant” apply where 49 CFR 172.203(l) requires them. It is not flagged as a severe marine pollutant.
How long does 12.5% sodium hypochlorite last in storage?
Degradation is continuous and driven by temperature, light and pH. Stored at 24 °C, available chlorine falls below half its original strength within about two years, and much faster if warm or exposed to light. Store at 15–18 °C in the dark, in vented containers, and re-titrate stock before use in any dosing application.
What happens if hypochlorite contacts ammonia or urea?
It forms chloramines, and with urea it forms nitrogen trichloride, which explodes spontaneously in air. Documented industrial explosions have occurred where hypochlorite reached ammonium-salt residues in effluent drains and in tanks cleaned without an intermediate rinse. Always rinse thoroughly between cleaning chemicals.
Why are there no OSHA or NIOSH exposure limits for sodium hypochlorite?
Because the solution itself is non-volatile, the airborne hazard in use is the chlorine it releases rather than the hypochlorite. Regulators therefore control chlorine directly. The only occupational limit specific to hypochlorite is the AIHA WEEL of 2 mg/m³ over 15 minutes.
Supply
We supply Sodium Hypochlorite 12.5% Solution in bulk from Chinese manufacturing plants, with a batch certificate of analysis and the manufacturer’s signed safety data sheet shipped against every consignment. Tell us the grade, volume and destination port and we will come back with packing options, lead time and a delivered price.
Sources
Every value on this page was taken from one of the following public authorities. Where an authority records no verified value, this page says so rather than substituting an estimate.
- PubChem — National Library of Medicine
- NIOSH Pocket Guide to Chemical Hazards
- ILO/WHO International Chemical Safety Cards
- CAMEO Chemicals — NOAA
- ECHA Classification & Labelling Inventory
- OSHA Annotated Permissible Exposure Limits
- eCFR Title 49 §172.101 Hazardous Materials Table
Compiled September 2026. Regulatory lists and classifications change; verify against the current source text before relying on this page for a compliance decision.