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Develop Bloody Fingerprints and Images. DeHaan JD, Clark JD, Spear TF,…

- - - - a. A faint product band for the DQA1 locus for the ninhydrin treated bloodstain
      - b. The larger loci in the AmpFLSTRÔ GreenI and the AmpFLSTRÔ Blue showed a minor reduction in signal intensity.
- - - - a. The entity providing forensic support at the crime scene should undertake a risk management evaluation of the issues. Specifically, upper management should assess the evidentiary worth and forensic value of using leuco crystal violet/crystal violet, versus, the potential health effects and long term liability from applying chemical compounds considered problematic.
      - b. Fully inform the law enforcement agency in control of the crime scene about the materials to be used and the potential short and long-term hazards involved to both forensic professionals and the public. Liability issues should be completely resolved, and clearly understood by all involved entities. A written and signed letter of notification (or other suitable documentation) should formalize the process.
      - c. At the crime scene, the target substrate receiving the leuco crystal violet formulation should be clearly identified. All practical measures should be taken to reduce the amount of substrate tested to an absolute minimum.
      - d. In the absence of any data regarding effective means for removal of leuco crystal violet from applied substrates, the target substrate(s) should be cut out or otherwise removed from those crime scenes where rehabitation of the building/structure is likely. The leuco crystal violet formulation can then be applied in an outdoor or better-controlled environment where improved ventilation is possible and residual contamination minimized.
      - e. Aerosolized leuco crystal violet formulation should be kept to an absolute minimum due to the lack of ventilation control and air flow at crime scenes. Off target spread of aerosolized leuco crystal violet and the subsequent exposure hazards clearly discourage spray application and should not be used. Other application methods need to be employed and/or researched.
      - f. All personnel applying the formulation and subsequently handling the evidence (target substrate) should wear appropriate personal protective equipment. This would include disposable, chemical protective body coverings, gloves and boots; and full-face supplied air or air-purifying respirator. The respiratory protection is used when the formulation is applied and the evidence handled in the 'wet' or 'fresh' state. If air-purifying respiratory protection is selected, canisters or chemical cartridges capable of removing amines, organic and aromatic compounds, and aerosols within the HEPA (High Efficiency Particulate Air) classification, are to be used.
      - g. All personal protective and evidence handling equipment which is visibly contaminated or reasonably anticipated to be contaminated with the applied formulation, is to be bagged and disposed of as hazardous waste, or subsequently cleaned in a controlled laboratory environment.
      - h. Good personal hygiene, including strict adherence to hand washing and the avoidance of hand-to-mouth activities during the use of leuco crystal violet is required.
      - i. Efforts are to be made to limit the number of individuals applying the formulation, handling the evidence after application, or otherwise potentially exposed to the leuco crystal violet formulation.
      - j. The law enforcement agency in charge of the crime scene is to post the scene, clearly providing notification of the type and kind of chemicals used in the processing of evidence and the general hazards associated with their exposure.
    - - a. The formulation is to be applied in a properly operating fume hood, with average hood inflow face velocities not less than 150 linear feet per minute. The 150 linear feet per minute is the minimum regulatory hood face velocity when working with carcinogenic materials. Airflow into the hood is to be smooth with no eddy or backwash currents.
      - b. Personnel applying the materials are to utilize chemical protective gloves, aprons or other body coverings, and protective eyewear such as goggles and/or faceshields.
      - c. Again, judicious use of the formulation is strongly recommended. Spraying is discouraged. Other application methods which generate minimal amounts of fugitive aerosols are encouraged.
      - d. Hand washing and the avoidance of hand-to-mouth activities are to be stringently enforced.
      - e. The written Chemical Hygiene Plan for the laboratory should be updated to reflect the use of potential carcinogenic materials and the control measures used to minimize personnel exposure.