| PROPOSED TEMPORARY AMENDMENT TO NFPA 921 |
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Add a new 6-5.9 to read
6-5.9 Canine Teams. Trained canine/handler teams can assist investigators in locating areas for collection of samples for laboratory analysis to identify the presence of materials that may be accelerants.
Add a new 9-5.3.4 to read:
9-5.3.4* Canine Teams. Properly trained and validated ignitable liquid detection canine/handler teams have proven their ability to improve fire investigations by assisting in the location and collection of samples for laboratory analysis for the presence of ignitable liquids. The proper use of detection canines is to assist with the location and selection of samples.
In order for the presence or absence of an ignitable liquid to be scientifically confirmed in a sample, a laboratory, in accordance with paragraph 9-5.3, should analyze that sample. Any canine alert not confirmed by laboratory analysis should not be considered validated.
Research has shown that canines have responded or alerted to pyrolysis products that are not produced by an ignitable liquid and have not always responded when an ignitable liquid accelerant was known to be present. If an investigator feels that there are indicators of an accelerant, samples should be taken, even in the absence of a canine alert.
The canine olfactory system is believed capable of detecting gasoline at concentrations below those normally cited for laboratory methods. The detection limit, however, is not the sole criterion, nor even the most important criterion for any forensic technique. Specificity, the ability to distinguish between ignitable liquids and background materials, is even more important than sensitivity for detection of any ignitable liquid residues. Unlike explosive or drug-detecting dogs, these canines are trained to detect substances that are common to our everyday environment. The techniques exist today for forensic laboratories to detect sub-microliter quantities of ignitable liquids, but because these substances are intrinsic to our mechanized world, merely detecting such quantities is of limited evidential value.
Current research does not indicate which individual chemical compounds or classes of chemical compounds are the key "triggers" for canine alerts. Research reveals that most classes of compounds contained in ignitable liquids may be produced from the burning of common synthetic materials. Laboratories, which use ASTM guidelines (see section 9-10), have minimum standards that define those chemical compounds that must be present to make a positive determination. The sheer variety of pyrolysis products present in fire scenes suggests possible reasons for some unconfirmed alerts by canines. The discriminatory ability of the canine to distinguish between pyrolysis products and ignitable liquids is remarkable, but not infallible.
The proper objective of the use of canine/handler teams is to assist with the selection of samples that have a higher probability of laboratory confirmation than samples selected without the canine's assistance.
Canine ignitable liquid detection should be used in conjunction with, and not in place of, the other fire investigation and analysis methods described in this guide.
Add a new A-9-5.3.4 to read:
A-9-5-3.4 For more information, see Kurz, M. et al., Evaluation of Canines for Accelerant Detection at Fire Scenes, Journal of Forensic Sciences, Vol. 39, No. 6, November 1994, pp. 1528-1536.
DeHann, J., Canine Accelerant Detection Teams: Validation and Certification, CAC News, California Association of Criminalists, July 1994.
Tindall, R. and Lothridge, K., An Evaluation of 42 Accelerant Detection Canine Teams, Journal of Forensic Sciences, Vol. 40, No. 4, July 1995, pp. 561-564
NFPA 921 TIA: RELEASED FOR PUBLIC COMMENT 1/96
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