Session 5F

Control Procedures for Water Reactive Chemicals

Upon completion of this session, you will learn additional methods to protect yourself from the hazards of water reactive chemicals.

It should  take you about 10 minutes to complete this training session.  When you have read through the material, you will be asked to answer 5 questions.

The information presented in this section is a summary of the hazards and controls for these compounds.  This is done for training purposes.  However, if you wish to get more detailed information, please consult the CHSP.  

Water reactive chemicals react violently with water releasing heat and in some cases explosive by-products.  Of chief concern are the alkali metals.  All alkali metals react vigorously with water to form the hydroxide. The rate of reaction increases as the atomic weight increases. Lithium reacts the slowest and poses the least hazard. The other metals react very quickly, generating great heat and splattering with the possible destruction of experimental apparatus. Hydrogen gas is also released in this reaction, and the heat generated from the reaction can ignite the hydrogen resulting in an explosion. A DOE document entitled "DOE-HDBK-1081-94, Primer on Spontaneous Heating and Pyrophoricity"  provides further guidance.

Control Measures

Line managers shall identify and evaluate the use of water reactives in the work area to determine the extent of the hazard and to evaluate the controls necessary to safeguard employee health.  MSDSs and other hazard databases for these materials should be reviewed and understood. AHDs maybe required for alkali metals.  An EH&S Industrial Hygienist should be contacted to provide further guidance.

Substitution

If possible substitute a non-water reactive material for the one being used. Otherwise, procure and use the minimum amount required for the operation.

Engineering Controls

Alkali metals shall be handled in an inert atmosphere such as in a dry argon-filled glove box made of materials that are compatible with the metal. Nitrogen may be used except when handling lithium.

Work Practices

• General traffic should be prohibited in areas where alkali metal operations are performed.
• Avoid all skin and eye contact with the material.  Where possible use tongs or appropriate tools to handle solids.
• Oxidized materials (with a white surface coating) makes the material more hazardous to handle because the oxide can flake off.  Note:  Materials with a yellow or orange coating may indicate the presence of peroxides which may detonate if cut or abraded.  Do not use these materials.  They should be isolated and disposed of.  Contact an EH&S Industrial Hygienis t for further guidance.
• All tools used to handle alkali metals must be dry, rust-free, clean, and composed of a material compatible with the metal. Tools can be dried by baking in an oven, desiccating in a vacuum, or rubbing with anhydrous dry soda ash.
• Assume that containers with alkali metals contain flammable hydrogen gas in the head space, even if stored under mineral oil or inert gas. Thus, no source of ignition shall be present where these containers are opened. Tools used to open the containers shall be of the spark less variety.

Personal Protective Equipment

The following is required when handling alkali metals:

• Safety glasses with side shields
• Laboratory coat (or equivalent)
• Chrome leather gloves or appropriate chemical resistant gloves.
• Closed toe shoes of leather construction
• Where solid metal is handled without a barrier (e.g., glove box), a fire retardant apron and face shield or goggles are required. Additional personal protective equipment shall be stipulated in the AHD in cases where large quantities of solid alkali metals are in use.

Storage

Storage procedures and incompatibilities can be found in Storage Guidelines of the CHSP.  General guidelines are presented below: 

• Separate alkali metals from incompatible chemicals.  In addition to being water reactive, alkali metals also react with oxygen, acids, halogenated hydrocarbons and carbon dioxide).  Consult the MSDS for specific storage guidelines.
• Store all metals in the container provided by the manufacturer
• Store alkali metals under mineral oil  or in an inert atmosphere (note: Lithium reacts with nitrogen.  Containers should be stored in a cool, dry environment, away from light and free from extremes of temperature and humidity).
• Use secondary containment.

Emergency Procedures

Fire and Spill Emergency Preparedness

• Anhydrous dry soda ash may be used for all metals except Lithium. Lith-X fire extinguishers must be used for Lithium. Alternative extinguishing agents such as powdered graphite or the commercial Met-L-X metal fire extinguishers may be used. Employees involved in metal work must be trained in the use of these extinguishing materials.
• Only trained personnel shall attempt to control small, contained fires or spills. If fumes are escaping into the breathing zone of these personnel, no local employee shall attempt to extinguish the fire. Large or unconfined fires or spills, or fires where the ventilation system does not contain all of the fumes, shall be handled only by the Fire Operations (7-911).

Skin or Eye Contact

• If any alkali metal fragment or drop enters the eye, it will immediately generate considerable heat which will likely result in severe eye damage. In such cases, the eyes shall be flushed with water from an eyewash/safety shower. Continue to flush the eye with water while someone dials 7-911 for emergency help.
• When alkali metal comes in contact with the skin, the first response is to strip off all contaminated clothing. If contact with the metal occurs at only one or two spots on the skin, it is best to wash off those areas with mineral oil. A container with at least one quart of mineral oil shall be available in alkali metal work areas. If contact with the metal is widely distributed over the body, a decision on the best course of first aid must be made immediately. If the material is already burning, the victim should be drenched continually under a safety shower until emergency help arrives. If the material is not burning (perhaps sodium or Lithium scraps), the metal should be removed by wiping the skin with mineral oil. In all cases, dial 7- 911 for assistance.

• Go to Specific Controls Exams
• Go to CHSP Table of Contents