Reactive chemicals react violently with water, air, or other chemicals to produce toxic gases, heat, fire, or explosion. Examples include metal hydrides, pyrophorics, water reactive chemicals, borohydrides, borane complexes, anhydrides, calcium, sodium, and metal powders. To safely manage reactive chemicals, consult the MSDS and adhere to the recommended storage and usage procedures outlined in the MSDS.
Air and Water Reactive Chemicals
Air reactive chemicals (also called pyrophoric chemicals) ignite spontaneously in air at temperatures below 54.4°C (130°F). Examples of air reactive chemicals are: silanes, alkyl metal derivatives, fine metal powders, metal hydrides, sodium methoxide, triethylaluminum, and white phosphorous.
Water reactive chemicals combine with water or moisture in the air to produce heat, ignite, or form explosive or toxic gases. These chemicals present a severe fire hazard because a sufficient amount of heat is often released to promote auto-ignition or to ignite surrounding materials. These chemicals can react spontaneously and rapidly even in controlled environments. Contact with the skin can cause severe burns. Examples of water reactive chemicals include: alkaline-earth metals (i.e., sodium, lithium, and calcium), aluminum chloride, anhydrous metal halides, anhydrous metal oxides, and non-metal oxides.
Peroxide Forming Chemicals
Compounds such as ethyl ether and tetrahydrofuran, can form unstable peroxides if managed or stored improperly. The formation of explosive peroxides can be accelerated by the introduction of contaminants, particularly metal oxides and oxygen. The development of crystals inside a bottle or around a cap or a “cloudy” appearance is indicative of peroxide formation. If a container that contains a peroxide forming chemical exhibits either of these characteristics or has remained in storage beyond the expiration date or one year, Safety Officer should be contacted to manage disposal of the container.
Temperature Sensitive Chemicals
Improper storage of temperature sensitive chemicals can result in a boiling liquid expanding vapor explosion (BLEVE) that can violently rupture the container. Additionally, the product involved in a BLEVE may be reactive, flammable, or harmful to health, thereby increasing the hazards and consequences to health and safety. Temperature sensitive chemicals should never be allowed to remain outside of a temperature controlled environment for any period of time longer than necessary to dispense or transport the chemical. If the chemical is no longer needed, leave the chemical in controlled climate storage and contact the Safety Officer to make special disposal arrangements.
Multi-nitrated Chemicals
Some multi-nitrated chemicals decompose violently when subjected to shock, heat, or other chemicals. Most multi-nitrated chemicals become more sensitive to shock and temperature when they become dry. Picric acid (phenol tri-nitrate or tri-nitrophenol) and 2,4-dinitrophenylhydrazine, are examples. Typically, these chemicals are manufactured and shipped with at least 30% water by weight. To prevent loss of water from these chemicals, containers must be kept tightly sealed.