Flammability and Explosibility

Dioxane is a highly flammable liquid (NFPA rating = 3). Its vapor is heavier than air and may travel a considerable distance to a source of ignition and flash back. Dioxane vapor forms explosive mixtures with air at concentrations of 2 to 22% (by volume). Fires involving dioxane should be extinguished with carbon dioxide or dry powder extinguishers.

Dioxane can form shock- and heat-sensitive peroxides that may explode on concentration by distillation or evaporation. Samples of this substance should always be tested for the presence of peroxides before distilling or allowing to evaporate. Dioxane should never be distilled to dryness.

Reactivity and Incompatibility

Dioxane can form potentially explosive peroxides upon long exposure to air. Dioxane may react violently with Raney nickel catalyst, nitric and perchloric acids, sulfur trioxide, and strong oxidizing reagents.

Storage and Handling

Dioxane should be handled in the laboratory using the ''basic prudent practices" described in Chapter 5.C, supplemented by the additional precautions for dealing with extremely flammable substances (Chapter 5.F). In particular, dioxane should be used only in areas free of ignition sources, and quantities greater than 1 liter should be stored in tightly sealed metal containers in areas separate from oxidizers. Containers of dioxane should be dated when opened and tested periodically for the presence of peroxides.


In the event of skin contact, immediately wash with soap and water and remove contaminated clothing. In case of eye contact, promptly wash with copious amounts of water for 15 min (lifting upper and lower lids occasionally) and obtain medical attention. If dioxane is ingested, obtain medical attention immediately. If large amounts of this compound are inhaled, move the person to fresh air and seek medical attention at once.

In the event of a spill, remove all ignition sources, soak up the dioxane with a spill pillow or absorbent material, place in an appropriate container, and dispose of properly. Respiratory protection may be necessary in the event of a large spill or release in a confined area.


Excess dioxane and waste material containing this substance should be placed in an appropriate container, clearly labeled, and handled according to your institution's waste disposal guidelines. For more information on disposal procedures, see Chapter 7 of this volume.

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