Calcium nitrate safety, handling and storage: hazards, classification, fire response and transport
Calcium nitrate is an oxidiser, not a fuel: it does not burn, but it intensifies fire when it meets combustible material, which is why it ships as UN 1454, Class 5.1, Packing Group III.[1][3][4] Most company notifications to the ECHA inventory (summarised in PubChem) list H302 harmful if swallowed (53.9%) and serious eye damage or irritation (H318 45.1%, H319 47.2%), while H272 (oxidiser) appears in 26.9% of reports.[1] A reported rat oral LD50 is 302 mg/kg, but other safety data sheets report higher values, so classification differs between suppliers.[1][17][18] It is not ammonium nitrate: India’s Ammonium Nitrate Rules apply to mixtures with more than 45% ammonium nitrate,[7] and the transport rules exempt calcium nitrate double-salt fertiliser with no more than 10% ammonium nitrate.[4][5] Store it dry, closed, and separate from combustibles, organics and reducing agents.[3][6]
Key facts at a glance
| Item | Value / answer |
|---|---|
| Transport classification | UN 1454, Class 5.1 (oxidising substance), Packing Group III[1][3][4][5] |
| GHS hazard statements most often notified | H302 (53.9%), H319 (47.2%), H318 (45.1%), H315 (43.7%), H272 (26.9%) of 1,286 reports[1] |
| Signal word and pictograms | Danger (H318 and H272 notifications) or Warning (H302, H319, H315); oxidiser flame-over-circle where H272 applies[1] |
| Oral toxicity, rat LD50 (reported values) | 302 mg/kg (PubChem); above 300 and below 2,000 mg/kg (OECD 423, tetrahydrate SDS); 3,900 mg/kg (HRSU SDS)[1][17][18] |
| Flammability | “Not combustible but enhances combustion of other substances”[1][3] |
| Behaviour in fire | Greatly intensifies burning of combustibles; may give off toxic oxides of nitrogen[1] |
| Melting point, anhydrous salt | About 560 °C; heating to decomposition emits toxic nitrogen oxides[1][3] |
| Water solubility | 121.2 g/100 mL (ICSC)[3] |
| Critical relative humidity (moisture uptake starts) | 46.7% RH at 30 °C for calcium nitrate[16] |
| Storage rule in one line | Separated from combustible substances and reducing agents; dry[3] |
| Drinking-water limits for nitrate | 10 mg/L as nitrogen (US EPA MCL); 50 mg/L as nitrate ion (WHO)[10][11] |
| Indian explosives rule threshold (ammonium nitrate) | Ammonium Nitrate Rules 2012 cover material with more than 45% ammonium nitrate by weight[7] |
Is calcium nitrate dangerous?
Calcium nitrate is a common, widely handled fertiliser salt, but it is not harmless. Its main hazards are three: it is an oxidiser that makes fires worse, it is harmful if swallowed, and its dust or solution can irritate or seriously damage eyes. The International Chemical Safety Card (ICSC 1037, IPCS/ILO) summarises it as a strong oxidant that reacts with combustible and reducing materials, with irritant effects on eyes and respiratory tract and a risk of methaemoglobin formation on ingestion.[3] Handled dry, in closed bags, away from fuels, the practical risk in a store is low; the serious incidents come from fire, contamination with combustibles, and swallowing or eye contact.
What is the GHS classification of calcium nitrate (H272, H302, H318)?
There is no single classification that every supplier uses. PubChem aggregates 1,286 company reports from 27 notifications to the ECHA Classification and Labelling Inventory, and the hazard codes are split.[1]
| Hazard statement | Meaning | Share of reports |
|---|---|---|
| H302 | Harmful if swallowed (acute toxicity, oral, Cat. 4) | 53.9%[1] |
| H319 | Causes serious eye irritation (Cat. 2) | 47.2%[1] |
| H318 | Causes serious eye damage (Cat. 1) | 45.1%[1] |
| H315 | Causes skin irritation (Cat. 2) | 43.7%[1] |
| H272 | May intensify fire; oxidiser (oxidising solid) | 26.9%[1] |
| H332, H314, H290 | Harmful if inhaled; severe skin burns and eye damage; may corrode metals | about 13% each[1] |
The differences reflect form (anhydrous or tetrahydrate), impurities and test data. A Sigma-Aldrich tetrahydrate SDS reports H302 and H318 and states the substance is not classified as oxidising on its test result,[17] whereas HRSU’s own SDS (titled for the tetrahydrate) lists oxidising solid Category 3 (H272) with milder oral, skin and eye categories (H303, H316, H320).[18] The safe approach for a buyer is to plan for the stricter set: treat it as an oxidiser, wear eye protection that seals, and do not rely on the least severe label. Always use the SDS supplied with the batch you receive.
What is the LD50 of calcium nitrate, and what is nitrate toxicity?
Reported oral LD50 values in rats range from 302 mg/kg in the PubChem record[1] to a band of more than 300 and less than 2,000 mg/kg in an OECD 423 test summarised in a tetrahydrate SDS,[17] and 3,900 mg/kg in HRSU’s SDS.[18] These are not contradictory so much as differently sourced and differently hydrated; they all place it well below “practically non-toxic” for swallowing, which is why H302 is the commonest label.
The systemic effect of concern is methaemoglobinaemia. Nitrate is converted to nitrite in the body; nitrite oxidises haemoglobin to methaemoglobin, which cannot carry oxygen, producing cyanosis (blue lips, fingernails and skin), headache, dizziness, confusion and, in severe cases, convulsions and unconsciousness.[1] Infants are most at risk, which is why drinking-water nitrate limits exist: 10 mg/L as nitrogen (US EPA) and 50 mg/L as nitrate (WHO), both set to protect bottle-fed infants.[10][11] The link between drinking-water nitrate and infant methaemoglobinaemia is discussed in the peer-reviewed literature, including how well the evidence supports it at a population level.[13] A 1992 CDC case report described an infant poisoned by well water containing 58 mg/L nitrate-nitrogen.[12] Treatment of acquired methaemoglobinaemia is medical (oxygen and, where indicated, methylene blue), not a first-aider’s task.[1]
Is calcium nitrate explosive or flammable?
Stated carefully:
- Not flammable. It does not burn; ICSC and PubChem both describe it as not combustible but enhancing combustion.[1][3]
- Not an explosive in transport or storage terms. It is a Class 5.1 oxidiser, not a Class 1 explosive, and it is shipped as Packing Group III, the lowest danger band within the class.[1][4][5]
- It makes fires worse and can contribute to explosion hazards in a fire. PubChem’s reactivity profile for calcium nitrate warns that if large quantities are involved in a fire, or the combustible material is finely divided, an explosion may result, and that mixtures with organic materials and certain reducing agents are hazardous.[1] The emergency guide for oxidisers (ERG Guide 140) says oxidiser products accelerate burning and may ignite combustibles.[1][2]
- The risk is contamination and fire, not the clean salt. That is the reason every guide says to keep it away from fuels, oils, wood, paper, organic chemicals and reducing agents.[3][6] This page gives no information on mixing it with anything; the correct instruction is the opposite.
Is calcium nitrate the same as ammonium nitrate or CAN?
No, and the regulatory treatment differs. Ammonium nitrate (NH4NO3) is a different compound that is named in Schedule 1 of India’s Manufacture, Storage and Import of Hazardous Chemical Rules,[8] and material containing more than 45% ammonium nitrate by weight falls under the Ammonium Nitrate Rules, 2012 (Explosives Act), which require licences for manufacture, transport, possession for sale and use.[7] The ERG oxidiser guide carries a specific caution that ammonium nitrate products may explode in fire or when contaminated; that warning is about ammonium nitrate, not about plain calcium nitrate.[1][2]
| Question | Calcium nitrate | Ammonium nitrate and AN-based fertilisers |
|---|---|---|
| Named in MSIHC Schedule 1 chemical list? | Not found in the list (checked)[8] | Yes, “Ammonium nitrate”[8] |
| Explosives licensing in India | Not an Ammonium Nitrate Rules product as such; the rules key on more than 45% ammonium nitrate[7] | Licences required above the 45% threshold[7] |
| Transport (UN 1454) | Class 5.1, PG III; commercial double-salt fertiliser with no more than 10% ammonium nitrate and at least 12% crystal water is exempt[4][5] | Separate UN entries and stricter rules (not covered here) |
| Emergency guide caution | Oxidiser: accelerates burning[1][2] | ERG Guide 140 adds explosion warnings for ammonium nitrate products[1][2] |
Calcium ammonium nitrate (CAN) is an ammonium-nitrate-based fertiliser, so its regulatory status depends on its ammonium nitrate content and should be confirmed with PESO rather than assumed from calcium nitrate’s status. See the calcium nitrate vs CAN comparison for agronomy. For a general encyclopedia overview of the compound, see Wikipedia (not used for any safety figure on this page).[19]
How should calcium nitrate be stored?
- Keep it dry and closed. Cornell EHS says to store solid oxidisers in original containers and keep them dry.[6] ICSC: “Separated from combustible substances and reducing agents. Dry.”[3]
- Segregate from fuels and incompatibles: flammables, combustibles, organics, reducing agents.[1][6][18] PubChem notes it should not be stored near organic or easily oxidisable material.[1]
- Keep it cool and out of direct sun in a ventilated area.[18] The tetrahydrate melts at about 43 °C,[18] so a hot store turns bagged salt into a sticky mass.
- Control humidity. The critical relative humidity of calcium nitrate is 46.7% at 30 °C, the point at which it starts to absorb moisture from air.[16] PubChem lists it as deliquescent.[1] Open bags in a monsoon-season warehouse will cake, then liquefy.
- Vehicle and floor hygiene. BAM’s transport guidance requires vehicles to be thoroughly cleaned of combustible residue before loading UN 1454.[4]
Shelf life. The sources consulted give no fixed expiry date for calcium nitrate; HRSU’s SDS says it is stable under ordinary conditions of use and storage.[18] In practice, quality is limited by moisture: the salt does not degrade chemically in a sealed bag but can cake or absorb water if the bag is damaged. Use first-in, first-out and check bag integrity.
How does calcium nitrate behave when heated?
The tetrahydrate melts near 43 °C and loses its water on heating;[15][18] the anhydrous salt melts at about 560 °C and, heated to decomposition, gives off toxic nitrogen oxides and leaves calcium oxide.[1][3][18] Those temperatures are far above any store, but a fire can reach them, which is why nitrogen oxide fumes are a firefighting hazard and breathing apparatus is required.[1][18]
What to do in a fire
- Evacuate and call the fire service. Tell responders it is a Class 5.1 oxidiser (UN 1454).[2]
- Use water. ERG Guide 140: small fire, use water, not dry chemical or foam; large fire, flood the area with water from a distance and move undamaged containers only if it can be done safely.[1][2] ICSC says to use media suitable for the surrounding fire.[3] Some SDS list foam or dry chemical, so follow the SDS for your specific product.[17]
- Wear self-contained breathing apparatus. Toxic nitrogen oxides are released.[1][18]
- Cool exposed containers with flooding quantities of water from as far away as possible.[1]
What to do in a spill
- Keep combustibles away (wood, paper, oil) from the spilled material.[1][2]
- Wear protective clothing, gloves and eye protection, and avoid creating dust.[1][18]
- Dry spill: shovel into a clean, dry container and cover loosely; do not get water inside the container.[1][2] ICSC adds: sweep into covered plastic containers and wash the remainder away with plenty of water.[3]
- Keep it out of drains and waterways, then dispose of it under local regulation.[18]
What PPE and first aid are needed?
| Exposure | Protection or response |
|---|---|
| Eyes | Safety spectacles at minimum (ICSC); chemical goggles or a face shield where dust is likely (HRSU SDS).[3][18] If exposed, rinse with plenty of water for several minutes, remove contact lenses if easy, then seek medical attention.[1][3] |
| Skin | Protective gloves and clothing.[3][18] Rinse with plenty of water for at least 15 minutes, remove contaminated clothing.[1][18] |
| Inhalation | Local exhaust or breathing protection against dust; a particulate respirator where dust is apparent.[3][18] Move to fresh air and rest.[1] |
| Swallowed | Rinse mouth, give one or two glasses of water, and seek medical attention.[1][3] Do not induce vomiting. Blue lips or skin, headache or confusion are signs of methaemoglobinaemia and need urgent care.[1] |
How is calcium nitrate classified for transport (UN 1454)?
The proper shipping name is CALCIUM NITRATE, UN 1454, Class 5.1, Packing Group III.[1][3][5] BAM’s dangerous-goods database for road transport lists hazard identification number 50, a limited-quantity allowance of 5 kg, and tunnel restriction code E.[4] Special provision 208 (also reproduced in Hong Kong’s dangerous goods database) states that commercial calcium nitrate fertiliser consisting mainly of a double salt of calcium nitrate and ammonium nitrate, containing no more than 10% ammonium nitrate and at least 12% water of crystallisation, is not subject to the dangerous goods rules.[4][5] Whether a given export consignment qualifies depends on its composition and the mode of transport. HRSU’s SDS lists UN 1454 for road and rail but marks IATA and IMDG as not regulated;[18] that entry should be confirmed against the current IMDG Code for the specific consignment before shipping.
What are the rules in India?
- Fertiliser Control Order, 1985 (made under the Essential Commodities Act) governs fertiliser quality, labelling and sale.[9] It lists nutrient specifications by product, and a 2021 amendment is summarised as adding a magnesium-fortified calcium nitrate suspension.[9][20] I could not confirm from the order text how calcium nitrate powder is scheduled. Check the current Schedule on the Department of Agriculture site for the powder specification.
- Ammonium Nitrate Rules, 2012 (PESO): apply above 45% ammonium nitrate; calcium nitrate itself is not the regulated substance.[7]
- MSIHC Rules, 1989 (Environment Protection Act): apply by named list or by hazard criteria and storage thresholds; calcium nitrate is not named in the Schedule 1 list I searched, while ammonium nitrate is.[8] A large store should still confirm its status with the factory inspectorate and state pollution control board.
What are the environmental effects?
Calcium nitrate has relatively low toxicity to fish and aquatic invertebrates in short-term tests,[1] and HRSU’s SDS reports a 96-hour rainbow trout LC50 above 98.9 mg/L.[18] The environmental issue is nitrate itself: excess fertiliser application is a recognised cause of elevated groundwater nitrate, which is why drinking-water limits exist.[10][11][14] Virginia Cooperative Extension notes nitrate-nitrogen at or above 10 mg/L has been linked to methaemoglobinaemia in infants under six months.[14] Do not let spilled product reach drains; apply to crop need only (see drip irrigation).
When calcium nitrate is NOT the right choice
- Do not store or mix it with fuels, oils, organics, sulphur-type reducing agents or acids. Contamination with combustible or reducing material is the main route to a serious incident.[1][3][6]
- Do not assume it is exempt from dangerous goods rules. UN 1454 is the default; the double-salt fertiliser exemption (no more than 10% ammonium nitrate, at least 12% crystal water) depends on the actual composition and mode of transport.[4][5]
- Do not treat it as ammonium nitrate or CAN in either direction: do not apply AN licensing to plain calcium nitrate, and do not assume CAN is covered by calcium nitrate’s status.[7]
- Do not rely on this page as your safety data sheet. Classifications vary between suppliers and hydrate forms; use the SDS issued for your batch and your local regulation.[1][17][18]
- Do not leave bags open in humid conditions. The salt is deliquescent and will cake and liquefy, which also makes it harder to handle safely.[1][16]
What HRSU supplies — and what it does not
HRSU Indore supplies fertilizer-grade calcium nitrate powder: 18.5–19% calcium, 15.5% minimum nitrogen, 100% water-soluble with 0% insoluble residue, in 25 kg and 50 kg bags, with a batch Certificate of Analysis and bulk or export supply. HRSU publishes a Safety Data Sheet, which classifies the product as an oxidising solid (H272) and lists UN 1454, Class 5.1, Packing Group III for road and rail.[18] That SDS is a summary; HRSU does not claim any explosives, food, pharma or other non-fertiliser grade. For export, ask HRSU to confirm the transport classification and any double-salt exemption for your consignment, shipping mode and destination before booking.
Request the HRSU SDS, TDS and batch COA
100% water-soluble · 0% insoluble residue · 25 kg & 50 kg bags · bulk/export available.
Buy online WhatsApp usFrequently asked questions
Is calcium nitrate explosive?
The clean salt is not an explosive: it is a Class 5.1 oxidiser, shipped at Packing Group III, not a Class 1 explosive.[1][4] However, reference sources warn that fire involving large quantities or finely divided combustibles can lead to an explosion, so it must be kept away from fuels and fire.[1] It is not ammonium nitrate.[7]
Is calcium nitrate flammable?
What is the UN number for calcium nitrate?
What are the hazard statements for calcium nitrate?
How should I store calcium nitrate?
How do you put out a fire involving calcium nitrate?
Is calcium nitrate toxic to humans?
Does calcium nitrate need an explosives licence in India?
Related guides
- Calcium nitrate vs CAN
- How calcium nitrate is made
- Buying bulk calcium nitrate from India
- Powder vs granular calcium nitrate
References
- Calcium nitrate (PubChem compound summary: GHS classification, toxicity, DOT, fire, reactivity, first aid) — U.S. National Library of Medicine / NCBI. Government database
- Emergency Response Guidebook 2024 (Guide 140, oxidizers) — U.S. DOT / PHMSA, via PubChem. Government guidebook
- ICSC 1037: Calcium nitrate (International Chemical Safety Card) — IPCS INCHEM (WHO / ILO). Intergovernmental body
- UN 1454 Calcium nitrate (Quickinfo, dangerous goods transport) — BAM, German Federal Institute for Materials Research and Testing. Government agency
- Dangerous Goods database: UN 1454 Calcium nitrate — Hong Kong Fire Services Department. Government regulator
- Appendix L: EHS Segregation Scheme (solid oxidizers) — Cornell University Environment, Health and Safety. University EHS
- Ammonium Nitrate Rules, 2012 — Petroleum and Explosives Safety Organisation (PESO), Government of India. Government regulator
- The Manufacture, Storage and Import of Hazardous Chemical Rules, 1989 — Ministry of Environment & Forests, Government of India (copy via Punjab Pollution Control Board). Government regulation
- The Fertiliser (Control) Order, 1985 — Government of India, via FAO FAOLEX. Government regulation
- Nitrate and nitrite in drinking-water (chemical fact sheet, Guidelines for Drinking-water Quality) — World Health Organization. Intergovernmental body
- Technical fact sheet on nitrate/nitrite (archived) — U.S. Environmental Protection Agency. Government regulator
- Methemoglobinemia attributable to nitrite contamination of potable water (Wisconsin infant case report, 1992) — CDC Morbidity and Mortality Weekly Report. Government
- Drinking-Water Nitrate, Methemoglobinemia, and Global Burden of Disease: A Discussion — PubMed Central, U.S. National Library of Medicine. Peer-reviewed
- Virginia Household Water Quality Program: Nitrate in Household Water (Publication 442-659) — Virginia Cooperative Extension (copy hosted by University of Maryland Extension). University extension
- Thermogravimetric examination of the dehydration of calcium nitrate tetrahydrate under quasiisothermal and quasi-isobaric conditions (Paulik, Paulik and Arnold), vol. 27, pp. 409-418, 1983 — Journal of Thermal Analysis, Springer. Peer-reviewed
- Critical relative humidity of fertilizers (technical paper, IFA Technical Conference, New Orleans, 2000) — International Fertilizer Industry Association. Industry association paper
- Safety data sheet: Calcium nitrate tetrahydrate (Sigma-Aldrich, hosted by Harper College) — Sigma-Aldrich via Harper College chemistry department. Supplier SDS
- Safety Data Sheet: Calcium Nitrate Tetrahydrate (HRSU Indore Pvt. Ltd.) — HRSU Indore Pvt. Ltd.. Manufacturer SDS
- Calcium nitrate — Wikipedia. Encyclopedia
- The Fertilizer (Inorganic, Organic or Mixed) (Control) Third Amendment Order, 2021 — TeamLease RegTech (summary of Government of India order). Regulatory news summary