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UCLA Department of Chemistry and Biochemistry

Chemical Safety Office

Safety Notes

Newsletter #9

August 1999


Lab fire caused by potassium ignition!
A researcher in Young Hall was slightly injured while performing an experiment on Saturday, July 17, 1999. He had been heating Potassium (K) in an evacuated tube, when the tube cracked, and the potassium started to smoke. He then tried to quench it in an isopropanol bath on the bench top. A large piece of potassium flaked off and ignited the isopropanol bath. According to the researcher, "a fireball hit me, and my arm caught on fire". Fortunately, he put out the fire on his arm immediately and wasn't injured. The sprinkler system in the building was activated and extinguished the remaining fire in the isopropanol bath. The fire alarm was sounded and Los Angeles Fire Department, the UCLA Haz Mat team, and the UCLA paramedics responded promply.

The water from the sprinkler system flooded four labs and office and computer spaces in lower floors in Young Hall, causing heavy damage to computers, notebooks, journals, etc.

What lessons can be learned from this fire?
ALWAYS quench alkalik metals in a fume hood!

When quenching potassium, start out with a mild quenching agent, such as t-butanol!
Plan ahead for possible emergencies! Poor housekeeping can contribute to the spread of fire. A laboratory fire can spread rapidly, destroying research, notebooks, computers, chemicals, etc.

Proper quenching techniques
  1. Always quench in a fume hood.
  2. Remove any potentially flammable materials from the immediate area.
  3. Start by using a mild quenching agent, such as t-butanol. Add it to the reactive metal slowly, with stirring. Hydrogen gas will be evolved.
  4. When metal no longer reacts with butanol, quench with isopropanol, then ethanol, and finally methanol.
  5. Let mixture stand in the fume hood for several hours to ensure complete quenching.
  6. Dispose of mixture as hazardous waste.
Consult Reference Books for more information. Two good ones are:

Linn, G., Sansone, E., Destruction of Hazardous Chemical in the Laboratory; Wiley: New York, 1990.

National Research Council, Committee on Prudent Practices for Handling, Storage, and Disposal in the Laboratory. Prudent Practices in the Laboratory: Handling and Disposal of Chemicals; National Academy Press; Washington, D.C., 1995

Remember that it is easier and safer to dispose of reactive metals as Hazardous Waste. Cover the metal with dry mineral oil and fill out a Hazardous Waste tag. Bring the Hazardous Waste to the Chemical Safety Office at Molecular Sciences, 2104. Phone: (20)6-3661.

At least two incidents recently have been reported in which laboratories were flooded by labs above them, both in Young Hall and Molecular Sciences. Improper fastening of tubing was to blame in both incidents. Because the water pressure fluctuates overnight, tubing used for cooling must be securely fastened onto the equipment and on the plumbing fixture. A number of methods have been used successfully:

  1. Wire tightly wrapped around apparatus and connection is a dependable method. Wire can be doubled for extra precaution. Wire should be wrapped tightly with a pair of pliers.
  2. Vacuum tubing clamps can be used for securing heavy walled rubber tubing.
  3. Pressure regulators can reduce the water pressure.
  4. 4. A controller that shuts down the power to the apparatus in case of water failure is available from Keith Stabe in the Microelectronics Shop.

Any leaking connections should be corrected before starting the experiment.

At any sign of flooding or water leakage, call the Department Mail and Information desk at ext. 5-4219 or, after hours, call Facilities Trouble Desk, at ext. 5-8406

Bill Peck, Chemical Safety Officer 4204 Young Hall, Ext. 6-3661
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Department of Chemistry & Biochemistry, UCLA