Ⅰ、Substances with Explosion Hazard When Reacting with Water
1. Sodium (Na)
Water Reaction: Sodium is highly reactive and can burn in the presence of oxygen, chlorine, fluorine, or bromine vapors. When it comes into contact with water or moisture, it reacts violently to release hydrogen gas, generating significant heat that can cause fires or explosions. Sodium metal exposed to air or oxygen can self-ignite and explode, causing molten droplets to scatter. It reacts vigorously with halogens, phosphorus, many oxides, oxidizing agents, and acids. When burning, it produces a yellow flame. It starts to vaporize at 100°C, and the vapor can erode glass.
Emergency Response and Firefighting Measures: Water, halogenated hydrocarbons (e.g., Halon 1211 fire extinguishing agent), sodium bicarbonate, and potassium bicarbonate should not be used as extinguishing agents. Instead, dry sodium chloride powder, dry graphite powder, dry sodium carbonate powder, dry calcium carbonate powder, or dry sand should be used to extinguish the fire.
2. Potassium (K)
Water Reaction: Potassium is highly reactive and can self-ignite in moist air. When it comes into contact with water or moisture, it reacts violently to release hydrogen gas, generating significant heat that can cause fires or explosions. Potassium metal exposed to air or oxygen can self-ignite and explode, scattering molten droplets. It reacts violently with water and carbon dioxide. It also reacts vigorously with halogens, phosphorus, many oxides, oxidizing agents, and acids. When burning, it produces a purple flame.
Emergency Response and Firefighting Measures: Water, halogenated hydrocarbons (e.g., Halon 1211 fire extinguishing agent), sodium bicarbonate, and potassium bicarbonate should not be used as extinguishing agents. Even dry graphite powder is not effective for potassium fires. Instead, dry sodium chloride powder, dry sodium carbonate powder, dry calcium carbonate powder, or dry sand should be used to extinguish the fire.
3. Sodium-Potassium Alloy (NaK)
Water Reaction: Sodium-potassium alloy is highly reactive and can self-ignite in moist air. When it comes into contact with water or moisture, it reacts violently to release hydrogen gas, generating significant heat that can cause fires or explosions. The alloy exposed to air or oxygen can self-ignite and explode, scattering molten droplets.
Emergency Response and Firefighting Measures: Water and foam should be prohibited for extinguishing fires involving sodium-potassium alloy. The fire should be extinguished using a metal fire extinguisher (such as sodium chloride) or dry sand.
4. Lithium (Li)
Water Reaction: Heating lithium may cause intense combustion or explosions. When exposed to air, lithium powder may self-ignite. Heating produces toxic fumes. It reacts violently with strong oxidizers, acids, and many compounds (such as hydrocarbons, halogens, halons, concrete, sand, and asbestos), presenting a fire and explosion hazard. When exposed to water, lithium reacts violently to produce highly flammable hydrogen gas and corrosive lithium hydroxide fumes.
Emergency Response and Firefighting Measures: Water, foam, carbon dioxide, and halogenated extinguishing agents should not be used. Extinguishing agents like sodium carbonate (soda ash), graphite powder, sodium chloride powder, and copper powder can be used for firefighting.
5. Magnesium Powder (Mg)
Water Reaction: Magnesium powder is highly flammable, producing intense white light and high heat during combustion. When exposed to water or moisture, it reacts violently to release hydrogen gas, generating significant heat that can lead to combustion or explosions. It reacts vigorously with chlorine, bromine, iodine, sulfur, phosphorus, arsenic, and oxidizers, posing a fire and explosion hazard. Magnesium powder can form explosive mixtures with air, and when the concentration reaches a certain level, it can explode upon encountering a spark.
Emergency Response and Firefighting Measures: Water, foam, and carbon dioxide should be strictly prohibited for extinguishing magnesium fires. The best firefighting method is to smother the fire with dry graphite powder and dry sand, isolating the fire from oxygen. Protective measures should be taken to safeguard the eyes and skin from burns caused by flying molten particles and from the intense light produced by burning magnesium.
6. Aluminum Powder (Al)
Water Reaction: Aluminum powder can self-ignite when exposed to moisture or water vapor. It can form explosive mixtures when combined with oxidizers. Contact with fluorine, chlorine, and other reactive substances can lead to violent chemical reactions. When exposed to acids or strong bases, it generates hydrogen gas, which can lead to combustion or explosion. Aluminum powder mixed with air forms explosive mixtures, which may explode when exposed to sparks if the concentration reaches a certain level.
Emergency Response and Firefighting Measures: Water, foam, and carbon dioxide should not be used for extinguishing fires involving aluminum powder. Appropriate dry sand or stone powder can be used to smother the fire.
7. Sodium Hydride (NaH)
Water Reaction: Sodium hydride is highly reactive and can self-ignite in moist air. When heated or exposed to moisture, acids, or humidity, it releases heat and hydrogen gas, which can lead to combustion and explosions. It reacts strongly with oxidizers, causing fire or explosion. When exposed to moisture or water, sodium hydride generates highly corrosive hydroxides.
Emergency Response and Firefighting Measures: Water, foam, carbon dioxide, and halogenated agents (such as Halon 1211) should not be used for extinguishing sodium hydride fires. Fires should be extinguished using a metal cover or dry graphite powder, dry dolomite powder, or similar dry agents to smother the fire.
8. Calcium Hydride (CaH2)
Water Reaction: Calcium hydride is highly reactive and reacts with moisture, water, or acids to release hydrogen gas, which can cause combustion or explosion. It reacts violently with oxidizers and metal oxides. When exposed to moisture or water, it forms corrosive hydroxides.
Emergency Response and Firefighting Measures: Water, foam, carbon dioxide, and halogenated agents (such as Halon 1211) should not be used for extinguishing calcium hydride fires. The fire should be smothered using a metal cover or dry graphite powder, dry dolomite powder, or other dry agents.
9. Potassium Hydride (KH)
Water Reaction: Potassium hydride is highly reactive and can react strongly with oxidizers, causing combustion or explosions. When heated or exposed to moisture, acids, or humidity, it releases heat and hydrogen gas, which can lead to combustion and explosions. When decomposed by heating, it produces highly toxic potassium oxide fumes. Potassium hydride powder, when heated, exposed to open flames, or in contact with oxidizers, can ignite and explode. When exposed to moisture or water, it generates highly corrosive hydroxides.
Emergency Response and Firefighting Measures: Water, foam, carbon dioxide, and halogenated agents (such as Halon 1211) should not be used to extinguish fires involving potassium hydride. The fire should be smothered with a metal cover or dry graphite powder, dry dolomite powder, or similar dry agents.
10. Calcium Cyanide (Ca(CN)2)
Water Reaction: Calcium cyanide is non-flammable but can release highly toxic cyanide gas when exposed to high heat or acids. It reacts violently with nitrates, nitrites, and chlorates, presenting an explosion hazard. When exposed to acids or moisture in the air, it absorbs water and carbon dioxide, decomposing to release highly toxic hydrogen cyanide gas.
Emergency Response and Firefighting Measures: Calcium cyanide is non-flammable, but in the event of a fire, efforts should focus on preventing the packaging from being damaged, which could lead to environmental contamination. Emergency responders must wear gas masks and full protective firefighting gear, working from an upwind direction to extinguish the fire. Suitable extinguishing agents include dry powder and sand. Carbon dioxide and acidic or alkaline fire extinguishing agents should not be used.
Ⅱ、Substances with Combustion Hazard When Reacting with Water
11. Trimethyl Borate (B(OC₆H₅)₃)
Water Reaction: Trimethyl borate vapors can form explosive mixtures with air, and it is highly flammable, prone to combustion and explosions when exposed to open flames or high heat. It reacts violently with oxidizers. When exposed to water or water vapor, it releases toxic and flammable gases. Its vapors are heavier than air and can travel long distances along the ground, with the potential for flashback if they encounter an ignition source. If exposed to high heat, the pressure inside containers may increase, posing a risk of rupture and explosion.
Emergency Response and Firefighting Measures: Emergency responders should wear gas masks and full protective firefighting gear, working from an upwind direction to extinguish the fire. The container should be moved away from the fire to an open area, if possible. If the container changes color or emits sounds from the safety pressure relief valve, evacuation must occur immediately.
Extinguishing agents: Dry powder, carbon dioxide, sand. Water and foam should not be used to extinguish the fire.
12. Sodium Hydrogen Sulfide (NaHS)
Water Reaction: Sodium hydrogen sulfide decomposes rapidly in moist air, forming sodium hydroxide and sodium sulfide while releasing heat, which can lead to self-ignition.
Emergency Response and Firefighting Measures: Emergency responders must wear a full-face filtered gas mask or an enclosed breathing apparatus, and full protective firefighting and chemical suits, working from an upwind direction to extinguish the fire. Containers should be moved away from the fire to an open area, if possible. Water spray should be used to cool containers in the fire area until the fire is extinguished.
If the container changes color or emits sounds from the safety relief valve, evacuation is required immediately. Extinguishing agents: Mist water, foam, dry powder, carbon dioxide, sand.
13. Phosphorus Pentasulfide (P₄S₁₀)
Water Reaction: Phosphorus pentasulfide poses a fire risk when exposed to open flames, high heat, friction, or impact. It decomposes when heated, releasing toxic gases, such as phosphorus and sulfur oxides. During combustion, it produces toxic and irritating smoke. It can heat up and even catch fire when exposed to moist air. It reacts violently with most oxidizers like chlorates, nitrates, perchlorates, or permanganates, forming highly sensitive explosive mixtures. When exposed to water or humid air, it decomposes into phosphoric acid and hydrogen sulfide, both of which are corrosive and irritating.
Emergency Response and Firefighting Measures: Emergency responders must wear full protective firefighting and chemical suits, working from an upwind direction to extinguish the fire. Extinguishing agents: Carbon dioxide, dry powder, sand.
14. Diethyl Zinc (C₄H₁₀Zn)
Water Reaction: Diethyl zinc can self-ignite in moist air. Heating may cause explosions. It is highly reactive and can undergo explosive reactions with alkenes, iodomethane, sulfur dioxide, and other chemicals. It reacts violently with bromine, water, and nitro compounds. It can ignite upon contact with air, ozone, methanol, or arsenic. It reacts violently with non-metal halides, producing self-ignitable products.
Emergency Response and Firefighting Measures: Emergency responders must wear a full-face filtered gas mask or an enclosed breathing apparatus, and full protective firefighting and chemical suits, working from an upwind direction to extinguish the fire.
The container should be moved away from the fire to an open area, if possible. Water spray should be used to cool the containers in the fire area until the fire is extinguished.
If the container changes color or emits sounds from the safety relief valve, evacuation is required immediately. Extinguishing agents: Dry powder, carbon dioxide, sand. Water and foam should not be used to extinguish the fire.
15. Triethylborane (TEB)
Water Reaction: Triethylborane is prone to self-ignition when exposed to air, oxygen, or oxidizers. When exposed to water, it decomposes to release flammable gases. It decomposes when heated, producing flammable and toxic gases.
Emergency Response and Firefighting Measures: Emergency responders must wear a gas mask and full protective firefighting gear, working from an upwind direction to extinguish the fire.
The container should be moved away from the fire to an open area, if possible. Water spray should be used to cool the containers in the fire area until the fire is extinguished.
If the container changes color or emits sounds from the safety relief valve, evacuation is required immediately. Extinguishing agents: Dry powder, carbon dioxide, sand. Water and foam should not be used to extinguish the fire.
Ⅲ、Substances with Toxicity Hazard When Reacting with Water
16. Potassium Phosphide (KH₃)
Water Reaction: Potassium phosphide is highly flammable and reacts violently with water, moisture, or acidic conditions to produce the highly toxic and self-igniting phosphine gas (PH₃). It also decomposes under high heat, releasing toxic fumes.
Emergency Response and Firefighting Measures: Emergency responders must wear gas masks to protect against toxic gases and work from a safe distance and upwind to extinguish the fire. Extinguishing agents: Dry powder, carbon dioxide, sand. Water and foam should not be used to extinguish the fire.
17. Phosphorus Trifluoride (PF₃)
Water Reaction: Phosphorus trifluoride reacts explosively with dioxygenyl fluoride (OF₂) and undergoes violent reactions with boranes, fluorine, and oxygen. When exposed to water or high heat, it releases large quantities of highly toxic gases.
Emergency Response and Firefighting Measures: Emergency responders must wear a full-face filtered gas mask or an isolated breathing apparatus, and full protective firefighting and chemical suits, working from an upwind direction to extinguish the fire.
Quickly cut off the gas supply and use water spray to protect personnel who are cutting off the gas. After this, appropriate extinguishing agents should be used depending on the fire’s cause.
The container should be moved away from the fire to an open area, if possible. Water spray should be used to cool containers in the fire area until the fire is extinguished.
18. Phosphorus Oxybromide (POBr₃)
Water Reaction: Phosphorus oxybromide reacts violently with water or water vapor, releasing heat and producing toxic and corrosive gases. It poses a fire hazard when in contact with organic materials. It decomposes under high heat, releasing toxic gases. When exposed to moisture, it is corrosive to most metals.
Emergency Response and Firefighting Measures: Emergency responders must wear gas masks and full protective firefighting suits, working from an upwind direction to extinguish the fire. The container should be moved away from the fire to an open area, if possible. Water spray should be used to cool containers in the fire area until the fire is extinguished. If the container changes color or emits sounds from the safety relief valve, evacuation is required immediately. Extinguishing agents: Mist water, foam, dry powder, carbon dioxide, sand.
19. Sodium Cyanide (NaCN)
Water Reaction: Sodium cyanide is non-flammable but reacts violently with nitrates, nitrites, and chlorates, presenting a risk of explosion. It releases highly toxic and flammable hydrogen cyanide gas when exposed to acids. In humid air or carbon dioxide, it slowly emits small amounts of hydrogen cyanide gas.
Emergency Response and Firefighting Measures: Sodium cyanide is non-flammable. In the event of a fire, efforts should focus on protecting the goods and preventing the packaging from being damaged, which could lead to environmental contamination. Emergency responders must wear gas masks and full protective firefighting suits, working from an upwind direction to extinguish the fire. Extinguishing agents: Dry powder, sand. Carbon dioxide and acidic or alkaline extinguishing agents should not be used.
20. Calcium Cyanide (Ca(CN)₂)
Water Reaction: Calcium cyanide is non-flammable but decomposes when exposed to high heat or acids, releasing highly toxic cyanide gases. It reacts violently with nitrates, nitrites, and chlorates, posing an explosion risk. When exposed to acids or moisture in the air, it absorbs water and carbon dioxide, decomposing to release highly toxic hydrogen cyanide gas.
Emergency Response and Firefighting Measures: Calcium cyanide is non-flammable. In the event of a fire, efforts should focus on protecting the goods and preventing the packaging from being damaged, which could lead to environmental contamination. Emergency responders must wear gas masks and full protective firefighting suits, working from an upwind direction to extinguish the fire. Extinguishing agents: Dry powder, sand. Carbon dioxide and acidic or alkaline extinguishing agents should not be used.
21. Bromine Acetyl Bromide (C₄H₆Br₂O)
Water Reaction: Bromine acetyl bromide is highly reactive with water, ethanol, and alkalis. It can ignite or explode when exposed to open flames, high heat, or oxidizing agents. When it comes into contact with water or ethanol, it reacts violently, releasing toxic and corrosive hydrogen bromide (HBr) fumes. It decomposes under high heat, producing toxic gases. It is corrosive to most metals when exposed to moisture.
Emergency Response and Firefighting Measures: Emergency responders must wear a full-face filtered gas mask or an isolated breathing apparatus, along with full protective firefighting and chemical suits, working from an upwind direction to extinguish the fire.
The container should be moved away from the fire to an open area, if possible. Water spray should be used to cool containers in the fire area until the fire is extinguished. If the container changes color or emits sounds from the safety relief valve, evacuation is required immediately. Extinguishing agents: Dry powder, carbon dioxide, sand. Water and foam should not be used to extinguish the fire.
22. Acetyl Iodide (C₂H₃IO)
Water Reaction: Acetyl iodide is flammable and reacts with water or ethanol, releasing toxic and corrosive gases. It is highly corrosive to most metals in the presence of moisture.
Emergency Response and Firefighting Measures: Emergency responders must wear full acid- and alkali-resistant firefighting suits. The container should be moved away from the fire to an open area, if possible. If the container changes color or emits sounds from the safety relief valve, evacuation is required immediately. Extinguishing agents: Dry powder, carbon dioxide, sand. Water and foam should not be used to extinguish the fire.
Ⅳ、Substances that Produce Hydrogen Chloride When Reacting with Water
23. Silicon Tetrachloride (SiCl₄)
Water Reaction: Silicon tetrachloride decomposes upon exposure to heat or water, releasing heat and producing toxic, corrosive fumes. It is corrosive to many metals, especially in humid air.
Emergency Response and Firefighting Measures: Emergency responders must wear full acid- and alkali-resistant firefighting suits. Extinguishing agent: Dry sand. Water should not be used.
24. Trichlorosilane (HSiCl₃)
Water Reaction: Trichlorosilane burns intensely when exposed to open flames. It decomposes under high heat, producing toxic chlorides. When it reacts with oxidizing agents, there is a fire hazard. It is highly volatile, smokes in the air, and reacts with water or water vapor, generating heat and toxic, corrosive fumes.
Emergency Response and Firefighting Measures: Emergency responders must wear a full-face filtered gas mask or an isolated breathing apparatus, along with full protective firefighting and chemical suits, working from an upwind direction to extinguish the fire. Extinguishing agents: Dry powder, dry sand. Water, foam, carbon dioxide, and acid or alkaline extinguishing agents should not be used.
25. Pentanoyl Chloride (C₅H₉ClO)
Water Reaction: Pentanoyl chloride reacts with water to release hydrogen chloride gas, which is irritating and corrosive. It may also react with oxidizing agents. Under high heat, it decomposes to produce highly toxic fumes.
Emergency Response and Firefighting Measures: Emergency responders must wear full acid- and alkali-resistant firefighting suits. The container should be moved away from the fire to an open area, if possible. Water spray should be used to cool containers in the fire area until the fire is extinguished. If the container changes color or emits sounds from the safety relief valve, evacuation is required immediately. Extinguishing agents: Dry powder, carbon dioxide, sand. Water and foam should not be used.
26. Isopentanoyl Chloride
Water Reaction: The vapor of isopentanoyl chloride can form explosive mixtures with air. It is highly flammable and explosive when exposed to open flames or high heat. It reacts violently with oxidizing agents. When it reacts with water, it releases hydrogen chloride gas, which is irritating and corrosive. Decomposition at high heat produces highly toxic fumes. It is corrosive to most metals in the presence of moisture. Exposure to high heat increases the pressure inside the container, which may cause it to crack or explode.
Emergency Response and Firefighting Measures: Emergency responders must wear gas masks, full protective firefighting suits, and work from an upwind position to extinguish the fire. If possible, containers should be moved from the fire area to an open space. Use water spray to cool containers in the fire area until the fire is extinguished. If the container changes color or emits sounds from the safety relief valve, evacuation is necessary immediately. Extinguishing agents: Dry powder, carbon dioxide, sand. Water and foam must not be used.
27. Fumaroyl Chloride (Trans-Butenedioyl Chloride)
Water Reaction: Fumaroyl chloride is flammable and may catch fire or explode when exposed to open flames or high heat. It reacts with oxidizing agents. When exposed to water, it undergoes a violent reaction, releasing hydrogen chloride gas, which is irritating and corrosive. Decomposition under heat releases highly toxic fumes. It is prone to self-polymerization, and the polymerization reaction accelerates with increasing temperature. It is corrosive to most metals in the presence of moisture. High heat can increase the pressure inside the container, leading to cracking or explosion.
Emergency Response and Firefighting Measures: Emergency responders must wear a filtered gas mask (full-face mask) or an isolated breathing apparatus, full protective firefighting and chemical suits, and work from an upwind position to extinguish the fire. If possible, move containers away from the fire area to an open space. Use water spray to cool the containers until the fire is extinguished. If the container changes color or emits sounds from the safety relief valve, evacuate immediately. Extinguishing agents: Dry powder, carbon dioxide, sand. Water and foam must not be used.
28. Sodium Dichloroisocyanurate
Water Reaction: Sodium dichloroisocyanurate is a strong oxidizing agent. It can ignite and burn upon contact with flammable materials or organic compounds. It reacts with nitrogen-containing compounds (such as ammonia or urea) to form explosive nitrogen trichloride. When heated or exposed to moisture, it decomposes and releases highly toxic fumes.
Emergency Response and Firefighting Measures: Emergency responders must wear full protective firefighting and chemical suits, and work from an upwind position to fight the fire. If possible, move containers from the fire area to an open space. Then, select the appropriate extinguishing agent based on the cause of the fire.
29. Iodine Trichloride
Water Reaction: Iodine trichloride decomposes under high heat, releasing corrosive and irritating fumes. It absorbs moisture or comes into contact with water, producing large amounts of corrosive fumes. It is highly corrosive.
Emergency Response and Firefighting Measures: Emergency responders must wear full acid/alkali-resistant firefighting suits. Extinguishing agents: Carbon dioxide, sand.
30. Arsenic Trichloride
Water Reaction: Arsenic trichloride decomposes upon contact with water and ultraviolet light, emitting white smoke and releasing corrosive and irritating hydrogen chloride gas. When mixed with metals like sodium, potassium, or aluminum, it can violently explode upon impact. It is highly corrosive.
Emergency Response and Firefighting Measures: Emergency responders must wear full protective firefighting suits and work from an upwind position to fight the fire. Extinguishing agent: Dry sand. Water must not be used.
