Facilities

LABORATORY & CHEMICAL HYGIENE PLAN

Corrosive Materials; Flammable Materials; Oxidizers; Moisture Reactive; Compressed Gases; Toxic and Poisonous Substances

Standard Operating Procedure No. 4

Moisture / Water Reactives

Scope: Liquids:  All Acids, Organic Halogens

Solids:  Metals, Sulfides, Amides, Carbides, Hydrides, Hydroxides, Trichlorides, Trifluorides, Tribromides

Gases:  Chlorine, Bromine, Fluorine

Hazards:   Liquids:  Acids react exothermically with water.  All acids are capable of causing severe thermal and chemical burns.  Organic halogens such as diethyl aluminum chloride and titanium tetrachloride are pyrophoric and capable of spontaneous ignition in contact with air or water, releasing hydrochloric acid vapors.

Solids:  All metals in their pure, powdered state are capable of immediate ignition when in contact with moist air.  Many react violently with water, such as sodium, potassium, and lithium to liberate flammable hydrogen gas.  During this process, the water solution becomes alkaline which can be extremely corrosive.  All other listed substances react violently with water to liberate flammable (hydrogen) and toxic gases (hydrogen sulfide).  Like the metals, the end product of the reaction with water is also alkaline.  Many, such as the hydrides, can ignite immediately upon contact with moist air.  Trichlorides and other triple halogenated solids react with moisture to liberate their corresponding halogen gas (e.g. trichloride will liberate hydrochloric acid and vapors).  These substances also react violently with water.

Gases:  The halogen gases are highly toxic and corrosive.  Technically, they are considered to be oxidizers.  They all react violently with water and inhalation of their fumes can be fatal.  All are capable of initiating combustion, sometimes violently, when contacted with a variety of substances.  Pressurized cylinders allow rapid release of the gas and present physical hazards from flying debris.  Introduction of contaminate (e.g. oil) into cylinder equipment such as valve regulators can cause explosion.

Storage: Liquids:  Segregate acids in approved “Corrosive” safety storage cabinets or separate shelving.  If shelving is used, store containers on lower shelf with a minimum of one-inch shelf lip.  Purchase glass containers for liquid acids with protective plastic film to minimize spills and splashing if dropped.  Ensure outside of bottles are clean after transfer to prevent corrosion of safety cabinet or shelving unit.  Transfer containers by using a safety bottle carrier when moving from one room to another.  Ensure secure storage of pyrophorics away from all other materials.  Do not store in direct sunlight.

Solids:  Store containers according to standard laboratory storage patterns in use (e.g. Flynn) and ensure segregation from sources of water or moisture.  Keep containers tightly sealed at all times.

Gases:  Cylinders must be secured at all times in restricted access area.  Valves must be shut off when not in use.  Cylinders may not be located within 20 feet of Oxygen cylinders.

PPE: Liquids:  Safety Goggles; Gloves; Instructor Lab-coat

Solids:  Safety Goggles; Gloves; Instructor Lab-coat

Gases:  Safety Goggles; Gloves; Instructor Lab-coat

Usage: Liquids:  Concentrated Acids must be transferred in hood.  Recap containers immediately after use.  When diluting acids, slowly add the acid to gently agitated water to prevent violent reaction.  Pyrophorics are not allowed outside of the hooded area.

Solids:  Handle all solids inside the hood.  Do not allow contact with water.  Ensure water sources are segregated.  Use nitrogen blanket and or purge when possible after consideration of the substance being used.  Ensure only the amount necessary for the experiment is removed from the container and the container is immediately resealed.

Gases:  Open cylinder valves and regulators slowly to prevent rupture of attached tubing.  Ensure cylinders are well secured.  Do not use gases near sources of oxidizable materials.  Ensure connection material and thread wrap is compatible with gas being used.  Close regulators and valves when finished with experiment.  Do not transport unless caps are securely fastened.

Waste: Liquids, Solids, Gases:  Contact Maine Department of Environmental Protection for details.  Wastes may be hazardous in nature requiring disposal by a DEP-licensed contractor.  

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