Could it react with water?

Key Points

  • Water-reactive substances react with water to produce heat and often hazardous products (such as toxicPoisonous; can injure or kill people or other organisms. or flammableEasy to ignite and burns readily. gases).
  • If a water-reactiveCan react vigorously when mixed with water or steam or when spilled into water; the reaction may generate hazardous gas or overpressurize a container. chemical is involved in a response, avoid exposing it to water, rain, water spray, or even humid air.
  • To find out whether a chemical is water reactive—and what happens when it reacts with water—review its chemical datasheet and use the reactivity prediction tool.
  • To find out if the chemical could generate toxic gases if spilled into water, check the UN/NA datasheet.

Backgrounder

If a hazardous substance spills into water—or if you're considering applying water or water spray to a spilled substance—check whether the substance reacts with water.

Many chemicals are considered water reactive because their reactionThe change that takes place when two or more substances interact to form new substances. with water could create a hazard. Either:

  • The reaction itself is violent.
  • The reaction produces products that are toxic, corrosiveLiquid or solid that can destroy human skin or lung tissue or corrode metals., flammable, and/or explosiveA material synthesized or mixed deliberately to allow the very rapid release of chemical energy (that is, an explosion). Also, a chemical substance that is intrinsically unstable and liable to detonate under conditions that might reasonably be encountered..
  • The reaction produces products (such as carbon dioxide gas) that are not hazardous in themselves but that can cause a container to overpressurize or can displace oxygen from the air.

Also, the reaction of a chemical with water releases heat (it's exothermicA chemical reaction that generates heat. Opposite of endothermic, in which heat is taken in from the surroundings.).

Some chemicals are so water reactive that they can react with rain, water spray, or even humidityAt a given temperature, the ratio of water vapor in the air to the maximum amount that can be held in the air at that temperature. in the air to create a hazard. Examples include lithium aluminum hydride, sodium metal, magnesium phosphide, and phosphorus pentachloride.

Note: As a general rule during a response, avoid exposing water-reactive chemicals to water, water spray, rain, or even very humid air.

Water Reactivity Information in CAMEO 365betÓéÀÖ

Follow the steps below to find out about a substance's water reactivity:

  1. Search for the chemical.
  2. In the Search Results pages, find the chemical datasheet, and click View Datasheet.
  3. Look in the Chemical Identifiers section of the datasheet. First, review the General Description for reactivity information. Next, check the NFPA 704 information to see the NFPANational Fire Protection Association (www.nfpa.org), a private, non-profit organization that produces technical data related to fire protection and prevention, including the widely used NFPA diamond that contains codes representing chemical hazards. instability (reactivity) and special ratings on the NFPA diamond for the chemical. A special rating of "W" or "No water" means the substance is unusually water-reactiveCan react vigorously when mixed with water or steam or when spilled into water; the reaction may generate hazardous gas or overpressurize a container.. Then review the DOT Hazard Label information (and the example placard images shown at the top of the datasheet) to see if the chemical has a Dangerous When Wet label.

    The chemical datasheet for aluminum phosphide. The water reactivity is noted on the example DOT placard, in the NFPA 704 diamond, and in the general description.
  4. Scroll down to the Hazards section. For more specific details about the chemical's water reactivity hazards, review Reactivity Alerts and Air & Water Reactions. Sometimes the other hazard sections, such as the Fire Hazard section in the example picture, may also have details about water reactivity hazards. See example Hazards sectionSee example Hazards section

    The Hazards section of the aluminum phosphide chemical datasheet.

  5. Click on the Add to My365betÓéÀÖ button to add it to the My365betÓéÀÖ collection.
  6. In the left sidebar, click View My365betÓéÀÖ.
  7. On the My365betÓéÀÖ page, click the Add Water button.
  8. In the left sidebar, click Predict Reactivity. A chart showing the potential reactivityThe tendency of a substance to undergo chemical change. The reactivity of most substances depends on the temperature and pressure of the surroundings, and on the chemicals with which it comes in contact. Under ordinary conditions, innately reactive substances are those that react rapidly with water, air, and other common components of the environment, as well as substances that self-react (decompose or polymerize). between the chemical and water is displayed. See example compatibility chartSee example compatibility chart

    A sample compatibility chart showing the potential reactivity results of mixing aluminum phosphide with water. The mixture is predicted to be corrosive, flammable, and toxic--as well as generating gas and heat. It is marked as Incompatible.

  9. Return to the chemical datasheet and then click on the UN/NA numberUnited Nations-North American number. (Also UN number or DOT number.) Four-digit number identifying an individual chemical or group of chemicals with similar characteristics. Required on shipping papers; often shown on placards. The four-digit number is often preceded by UN (such as UN1219). link (near the top) to go to the UN/NA datasheet.
  10. If the chemical could generate large amounts of toxic-by-inhalationA route of chemical exposure in which a toxic material is brought into the bloodstream as particles or volatile compounds breathed into the lungs and nasal passages. gases if spilled into water, an ERGThe Emergency Response Guidebook (ERG): A Guidebook for First Responders During the Initial Phase of a Dangerous Goods/Hazardous Materials Transportation Incident is a book used by emergency planning and response personnel when responding to situations involving hazardous materials. Table 2 green section will be shown on the UN/NA datasheet. See example ERG Table 2 sectionSee example ERG Table 2 section

    UN/NA datasheet for UN/NA 1397 (aluminum phosphide), which has a toxic-by-inhalation gases section (ERG Table 2).

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