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Standards and Guidelines - Forensic Science Communications - April 2006

Standards and Guidelines - Forensic Science Communications - April 2006

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April 2006 - Volume 8 - Number 2

Standards and Guidelines

Quality Assurance Guide for the Forensic Analysis of Ignitable Liquids

Fire Laboratory Standards and Protocols Committee
Scientific/Technical Working Group for Fire and Explosions

Scope | Significance and Use | Terminology | Physical Plant | Personnel | Quality Manual Documentation | Evidence ControlAnalytical Procedures | Instrumentation | Technical and Administrative Review | Chemicals, Reagents, and Supplies | Proficiency and Competency Testing | Verification and Validation | Laboratory Audits | Deficiency of Analysis | Health and Safety 

1. Scope
  1.1. The goal of a laboratory's fire debris analysis program is to provide quality analytical service for fire investigations. It is the goal of these guidelines to provide a framework of quality management in the processing of fire debris evidence, including evidence handling, management practices, qualitative analysis, and reporting.
  1.2. It is recognized that other types of evidence may be encountered at a fire scene; however, the scope of this document is limited to the analysis of ignitable liquids and ignitable liquid residues.
2. Significance and Use
  2.1. This document pertains to the analysis of samples suspected to contain ignitable liquids or their residues. It is intended to serve as a framework for the development and assessment of a quality assurance program.
3. Terminology
  3.1. Administrative review: A review of a report for compliance with laboratory policy and editorial correctness.
  3.2. Audit: A review conducted to compare various aspects of a laboratory's performance with established criteria.
  3.3. Blank: A quality-control tool needed to establish an analytical baseline for interpretation. A quality-control check used to detect potential contamination.
  3.4. Calibration: The process of assigning a known value within specified limits to the scale reading of an instrument.
  3.5. Certified reference material (CRM): A reference material that has one or more of its property values certified by a technical procedure and accompanied by or traceable to a certificate or other documentation that has been issued by a certifying body.
  3.6. Chain of custody: Procedures and documents that account for the integrity of an item of evidence by tracking its handling and storage from its point of collection to its final disposition.
  3.7. Competency test: An assessment of a person's knowledge, skills, and ability to perform his or her assigned duties.
  3.8. Deficiency of analysis: An erroneous analytical result or interpretation or an unacceptable deviation from an established policy or procedure in an analysis.
  3.9. Examiner: A person who receives and examines evidence, interprets results, writes reports, and testifies on casework findings.
  3.10. Ignitable liquid: A liquid capable of burning.
  3.11. Official methods: Validated analytical methods that have been accepted and published by an appropriate standardization organization.
  3.12. Proficiency test: An evaluation of personnel and laboratory procedures through the examination and interpretation of a prepared sample.
  3.13. Quality assurance (QA): Planned and systematic actions to provide confidence that a service will meet established requirements.
  3.14. Quality control (QC): Operational procedures designed to ensure quality results or indicate system failure.
  3.15. Reference collection: A collection of materials, substances, and/or objects of known properties and/or origin that may be used to aid in the identification or classification of unknown items.
  3.16. Reference ignitable liquid: An ignitable liquid that has had its composition verified and that is used to aid in the identification and classification of unknown ignitable liquids and their extracted residues.
  3.17. Technical peer: An examiner technically competent in fire debris analysis and related interpretation.
  3.18. Technical review: Review by a technical peer for technical accuracy and use of appropriate methodology and documentation.
  3.19. Validation: The acquisition of information needed to assess the reliability of a procedure and to determine the conditions under which acceptable test results can be obtained.
  3.20. Verification: Confirmation that a validated method works as intended in a given environment.
4. Physical Plant
  4.1. The laboratory shall contain adequate space to perform required analytical functions and prevent contamination.
  4.2. Chemical fume hoods shall be provided and maintained.
  4.3. Adequate measures shall be taken to ensure good housekeeping in the laboratory.
    4.3.1. Housekeeping products that may be exposed to evidence and sampling devices shall be free of potential contaminants.
  4.4. Adequate facilities must be provided to ensure the proper safekeeping of physical evidence, reference materials, and records.
    4.4.1. Refrigerators/freezers shall be available for the storage of samples prone to degradation (e.g., soil, biological samples).
    4.4.2. Storage areas must be adequately ventilated to prevent incidental contamination.
    4.4.3. Separate areas should be available for storing fire debris evidence and bulk ignitable liquid submissions.
  4.5. Appropriate storage must be available for storing chemicals, reagents, and supplies. This storage area shall be separate from the evidence storage area.
  4.6. Separate areas should be available for processing suspected ignitable liquid residues (debris samples) from other ignitable liquids (reference collection and bulk liquid evidence submissions), or other controls must be in place to avoid incidental contamination.
5. Personnel
  5.1. Job Descriptions
    5.1.1. Quality Assurance Manager
      5.1.1.1. A person who is responsible for maintaining and monitoring the quality management system.
    5.1.2. Technician/Laboratory Aide
      5.1.2.1. A person who performs basic laboratory duties but does not examine or handle evidence.
    5.1.3. Support Analyst
      5.1.3.1. A person who processes evidence but does not issue reports for court purposes.
    5.1.4. Analyst
      5.1.4.1. A person who examines and analyzes evidence for the presence of ignitable liquids and ignitable liquid residues or directs such analyses.
      5.1.4.2. A person who interprets ignitable liquid analysis results, writes reports based upon those results, and testifies as an expert on those findings.


5.2. Qualifications/Education
    5.2.1. Quality Manager
      5.2.1.1. Education, skills, and abilities commensurate with responsibilities.
    5.2.2. Laboratory Technician
      5.2.2.1. Education, skills, and abilities commensurate with responsibilities.
      5.2.2.2. On-the-job training specific to duties.
    5.2.3. Support Analyst
      5.2.3.1. Documented on-the-job training specific to responsibilities, and
      5.2.3.2. Demonstrated competency in the specific areas of responsibility through successful completion of a competency assessment, and
      5.2.3.3. Meets the requirements of at least one of the following:
        5.2.3.3.1. A minimum of a bachelor's degree in a natural science or equivalent degree, which shall include lectures and associated laboratory classes in general, organic, and analytical chemistry; or
        5.2.3.3.2. A minimum of one year of practical experience in the area of fire debris analysis.


  5.2.4. Analyst
      5.2.4.1. Documented on-the-job training specific to responsibilities, and
      5.2.4.2. Demonstrated competency in the specific areas of responsibility, and
      5.2.4.3. A minimum of a bachelor's degree in a natural science or equivalent, which shall include lectures and associated laboratory classes in general, organic, and analytical chemistry.


5.3. Training
    5.3.1. The laboratory must establish a written training program for new analysts and for analysts in need of remedial training.
    5.3.2. The new-analyst training program should include elements as described in Training Guidelines for the Fire Debris Analyst: Basic Training Requirements Set Forth by TWGFEX Laboratory Fire Debris Training and Education Committee. For analysts in need of remedial training, the program should be customized to ensure that deficiencies are resolved.
    5.3.3. Training programs shall include documented standards of performance and assessment.
    5.3.4. Training shall include a period of supervised casework representative of the types of analyses the employee may perform.
    5.3.5. Upon completion of the training program, documentation demonstrating that the trainee has achieved the required level of competence shall be generated and maintained.
  5.4. Professional Development/Maintaining Qualifications
    5.4.1. In order to maintain qualifications, analysts should:
      5.4.1.1. Successfully complete competency/proficiency testing in fire debris analysis annually.
      5.4.1.2. Actively participate in casework examinations.
      5.4.1.3. Attain a minimum requirement of 20 hours per year of continuing education of a chemical/technical nature relevant to the analyst's duties. This can be achieved in a number of ways, including one or more of the following:
        5.4.1.3.1. Attendance at a relevant professional forensic association meeting or workshop.
        5.4.1.3.2. Attendance in a relevant technical training course.
        5.4.1.3.3. Completion of relevant college-level courses.
        5.4.1.3.4. Participation in and/or presentation of relevant research or method development.
6. Quality Manual Documentation
  6.1. In addition to case documentation, the laboratory must maintain the following:
    6.1.1. Test methods/procedures for ignitable liquid and ignitable liquid residue analysis for each technique used.
    6.1.2. Policies and procedures for and documentation of maintenance and use of reference ignitable liquids, including acquisition, testing, and classification.
    6.1.3. Policies and procedures for and documentation of preparation and testing of prepared reagents used in ignitable liquid analysis.
    6.1.4. Evidence-handling protocols and documentation of chain of custody.
    6.1.5. Policies and procedures for and documentation of equipment calibration and maintenance.
    6.1.6. Policies and procedures for and documentation of proficiency and competency testing.
    6.1.7. Policies for personnel training and qualifications.
    6.1.8. Documentation of professional development.
    6.1.9. Quality assurance protocols and documentation of audits.
    6.1.10. Security protocols.
    6.1.11. Health and safety policies.
    6.1.12. Procedures for and documentation of method validations and/or verifications.
7. Evidence Control
  7.1. The laboratory shall maintain written policies for evidence control to ensure the integrity of the evidence while in the laboratory's custody.
  7.2. Access to the operational areas of the laboratory and areas in which evidence is stored must be controlled and limited.
  7.3. Sample storage must prevent loss, deterioration, and contamination.
  7.4. Procedures should be in place to ensure that samples are properly labeled throughout the analytical process.
  7.5. Procedures must be established to document and preserve the chain of custody for each item of evidence.
  7.6. Evidence must be properly packaged, secured, and sealed.
    7.6.1. Containers should be vapor-tight and free of ignitable liquid contaminants.
      7.6.1.1. It is recommended that a representative sample from batches of fire debris evidence containers be analyzed for incidental contamination prior to use.


7.7. The laboratory must maintain records of requests for analysis, to include:
    7.7.1. A unique identifier assigned to each case or record.
    7.7.2. Submission documents.
    7.7.3. Identifying information of the submitting parties.
    7.7.4. A description of the items submitted.
    7.7.5. A record of the chain of custody.
  7.8. A description of the evidence shall be compared to the documentation prior to analysis. Significant discrepancies shall be documented and resolved prior to the completion of the analysis.
      7.8.1. Any alteration of the evidence must be documented in writing.
8. Analytical Procedures
  8.1. Analytical Procedures for Ignitable Liquid Analysis
    8.1.1. The laboratory shall have and shall follow written analytical procedures.
    8.1.2. The laboratory shall establish work practices to prevent contamination of evidence during processing, analysis, and storage.
    8.1.3. The analysis of various substrates for the presence of ignitable liquids or ignitable liquid residues can be accomplished by a variety of methods.
      8.1.3.1. Preference should be given to using nondestructive techniques. When multiple techniques are used, nondestructive techniques should be performed first.
    8.1.4. Sample handling after analysis
      8.1.4.1. Laboratory extracts should be preserved for potential reanalysis.
    8.1.5. All analytical procedures used must be validated and verified. The use of official methods is recommended.
      8.1.5.1. All new or unofficial methods must be validated prior to use in casework.
      8.1.5.2. Official methods must be verified prior to use in casework.
    8.1.6. Blanks representing each extraction technique should be run with each case to demonstrate that sampling devices, chemicals, and processes do not result in contamination of evidence.
  8.2. Reference Ignitable Liquids
    8.2.1. Reference ignitable liquids shall be maintained by the laboratory; however, certified reference materials are not required.
    8.2.2. The classification of reference materials must be authenticated prior to use by the use of gas chromatography-mass spectrometry and/or by pattern recognition comparison to appropriate reference documentation.
9. Instrumentation
  9.1. Instruments must be routinely monitored to ensure proper performance.
    9.1.1. Written procedures for monitoring instrument performance and maintenance shall be established.
    9.1.2. Documentation of instrument performance and maintenance shall be maintained.
  9.2. Equipment
    9.2.1. Only suitable and properly operating equipment shall be used.
10. Technical and Administrative Review
  10.1. All casework shall be subjected to technical and administrative review.
  10.2. The laboratory must have a written policy establishing the protocols for technical and administrative case review.
  10.3. The laboratory must have a written policy to determine the course of action should an analyst and reviewer disagree.
  10.4. Technical review shall be documented and maintained.
    10.4.1. A standard technical review should answer the following questions:
      10.4.1.1. Is there adequate documentation relating to all of the materials examined?
      10.4.1.2. Have all of the appropriate analyses been carried out?
      10.4.1.3. Have all of the relevant QA/QC procedures been followed?
      10.4.1.4. Are the conclusions reached justified and appropriate?
      10.4.1.5. Is the statement/report accurate?
  10.5. Administrative review should ensure editorial correctness and adherence to laboratory policies.
11. Chemicals, Reagents, and Supplies
  11.1. Chemicals and reagents used in ignitable liquid/ignitable liquid residue analysis must be of sufficient purity.
  11.2. Documentation for reagents prepared within the laboratory must include identity, concentration (where appropriate), date of preparation, identity of the individual preparing the reagents, and the expiration date (if appropriate).
  11.3. Each container of extraction solvents must be tested for interfering contaminants prior to use, and the resulting documentation must be maintained.
  11.4. Chemical and reagent containers shall be dated and initialed when received and when first opened.
12. Proficiency and Competency Testing
  12.1. Each laboratory shall have written protocols for testing the competency of its laboratory analysts.
  12.2. Each laboratory should participate in at least one external proficiency test annually.
  12.3. Laboratories shall perform proficiency testing in order to evaluate the laboratory's performance.
    12.3.1. Proficiency tests should be representative of the laboratory's normal casework.
    12.3.2. Standard laboratory procedures shall be used for all proficiency-test analyses.
  12.4. Each analyst should be competency-tested in fire debris analysis at least once per year.
    12.4.1. Competency-testing samples should be representative of the laboratory's normal casework.
    12.4.2. Standard laboratory procedures shall be used for all competency-test analyses.
    12.4.3. A single test may serve as both a competency test and a proficiency test.
13. Verification and Validation
  13.1. The laboratory shall use validated techniques and procedures. Official methods are considered valid.
  13.2. All methods, including official methods, shall be verified to ascertain proper performance in the individual laboratory.
  13.3. Validation and verification procedures shall be documented.
    13.3.1. Validation should include specificity, limits of detection, reproducibility, advantages, and the limitations of the technique.
  13.4. New techniques developed for the characterization, identification, and comparison of ignitable liquids and their residues should be based on accepted scientific principles. Validation studies to establish the reliability of the technique must be performed prior to use in casework.
14. Laboratory Audits
  14.1. Audits of laboratory operations should be conducted at least once per year.
  14.2. Records of each audit must be maintained and should include the date of the audit and its scope, the name(s) of the auditor(s), the findings, and the corrective actions taken.
15. Deficiency of Analysis
  15.1. In the course of examining ignitable liquids and their residues, laboratories may expect to encounter some operations or results that are deficient in some manner. Each laboratory must have a written policy to deal with such deficiencies. This policy must include a definition of a deficiency and a protocol for addressing and correcting such deficiencies.
16. Health and Safety
  16.1. The laboratory must have a documented health and safety program in place to meet the needs of the laboratory.