Page 6 - A Burning Question Fire Debris

5. Repeat the above procedure for the six FIRE SAFETY PRECAUTIONS
DEBRIS EVIDENCE SAMPLES using the 6. As this lab involves breaking the ends off glass
GASOLINE REFILL DISPENSER. colorimetric tubes, the presence of sharp edg es
are possibile. Caution should be exercised when
handling broken glass. Additionally, stu dents
RUNNING THE LAB should be reminded to only handle glass while
During the labs, instruct students that the samples wearing appropriate personal protective equipment
should not be heated excessively, as heating is only including, at a minimum, gloves and eye protection.
necessary to volatilize the ignitable liquid present 7. Students should be reminded to exercise
in the debris. Heating in excess may degrade the diligence during heating and when handling
compound present. heat ed containers.

NOTES

 A tight seal is essential around the colorimetric tube so that the only method of escape for the
volatilized ignitable liquid is through the tube. Failure to properly seal the tube could result in a
false negative reading.
 The presence of an ignitable liquid in fire debris, while it could be an indicator of arson, is not
conclusive for arson. An ignitable liquid may have been present before the fire occurred, such as
if a container of gasoline or diesel fuel had spilled in the vehicle.

6 THE MYSTERY OF LYLE AND LOUISE