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Fire Scene Evidence Collection Guide

Oils and Greases

Motor Vehicle Fluids

Detailed Procedure:

The purpose of collecting vehicle fluids is to determine whether or not the vehicle was properly functioning at the time of the fire. Evaluating fluids from vehicles for the presence of wear metals, such as iron, aluminum, lead, and copper allows the investigator to assess the wear on the engine and transmission at the time of the fire. The levels of wear metals could also determine if the components were operating properly or had abnormal wear causing expensive repair problems for the owner. Vehicular fluid analysis can also identify motor fluids such as motor oil, transmission fluid, brake fluid, and power steering fluid. The presence of contaminates in motor fluids, such as dirt and sugar, can also be analyzed. Severe conditions in the transmission and engine could provide motive for some insured to commit insurance fraud.

To collect motor oil and/or transmission fluid from a vehicle:

  1. Photograph the area.

  2. Wear new, unused, clean latex or nitrile gloves.

  3. Using a 6-foot section of 0.25-inch disposable OD plastic tubing, slide the tubing down the dipstick tube of the engine or transmission. Sometimes, the tube will get stuck during insertion, so more than one attempt may be required.

  4. Once you feel the tube has hit the bottom of the engine or transmission, pull the tube up about 2 inches.

  5. Remove the lid from a clean, new sample bottle and screw the bottle onto the hand-operated fluid extractor pump.

  6. Insert the exposed end of the tube to the fluid extractor pump, until the tube is about an inch inside the bottle.

  7. Pump the fluid extractor pump. This will pump the fluid from the engine or transmission into the sample bottle.

  8. Fill the sample bottle approximately 3/4 full of fluid. This is the amount required for an effective analysis.

  9. Remove the bottle from the fluid extractor pump and replace the lid removed earlier.

  10. Place evidence tape across the sealed top of the bottle. Initial and date the tape.

  11. Label the sample bottle with identifying information, including case number, date, exhibit number, a brief description including recovery location, and your name. Note the make and model of the vehicle, size, and make of engine (for oil analysis tests only), type of fuel used, miles on the engine or transmission, miles on the fluid and filter (since last change). Provide this information to the laboratory when you submit the sample. If some of the information cannot be obtained, gather as much information as possible. Please note: It is vital that you label each fluid (motor oil, transmission fluid, gasoline, brake fluid, etc.) at the time of collection. Many fluids look similar upon collection.

  12. Store the sample bottle in a secure location until you are able to transport it to the laboratory.

Contact your local laboratory if you have any problems collecting the sample or questions regarding testing.

To collect gasoline/diesel from a vehicle:

Fuel extraction may be performed in a number of different ways. The appropriate sampling technique is determined by the nature of the test desired. Consult your laboratory for assistance, if necessary.

  1. Photograph the area.

  2. Wear new, unused, clean latex or nitrile gloves.

  3. Collect the sample using the appropriate method:

    1. To sample fuel from a vehicle tank, use a hand-operated extraction pump with 0.25-inch disposable OD plastic tubing inserted in the filler neck. Fill the glass sample bottle approximately 3/4 full for an effective analysis. Recap the bottle to seal.

    2. To sample fuel from the fuel filter, remove and collect the fuel filter. Wrap the fuel filter in new, clean paper towels and place them into a new, clean metal paint can. Seal the can.

    3. To sample fuel from the fuel injectors, remove the fuel injectors from the engine. Wrap the injectors in new, clean paper towels and place them into a new, clean metal paint can. Seal the can.

    4. To sample fuel from the fuel lines, disconnect the fuel line and drain the fuel into a glass sample bottle. Re-cap the bottle to seal.

  4. Place evidence tape across the sealed top of the bottle. Initial and date the tape.

  5. Label the container with identifying information, including case number, date, exhibit number, a brief description including recovery location, and your name. Note the make and model of the vehicle, size, and make of engine (for oil analysis tests only), type of fuel used, miles on the engine or transmission, miles on the fluid and filter (since last change). Provide this information to the laboratory when you submit the sample. If some of the information cannot be obtained, gather as much information as possible and submit it. Please note: It is vital that you label each fluid (motor oil, transmission fluid, gasoline, brake fluid, etc.) at the time of collection. Many fluids look similar upon collection.

  6. Store the container in a secure location until you are able to transport it to the laboratory.

Contact your local laboratory if you have any problems collecting the sample or questions regarding testing.

To collect brake fluid from a vehicle:

  1. Photograph the area.

  2. Wear new, unused, clean latex or nitrile gloves.

  3. Brake fluid is frequently extracted from the brake line nipple near the rotors, or it can be extracted from the master cylinder or brake fluid reservoir. Use a new bulb and tube manual suction device, such as a syringe or disposable pipette.

  4. Remove the lid from a clean, new sample bottle.

  5. Use the syringe or pipette to extract fluid from the reservoir and then deposit that fluid in the sample bottle.

  6. Fill the sample bottle approximately 3/4 full of fluid. This is the amount required for an effective analysis.

  7. Place evidence tape across the sealed top of the bottle. Initial and date the tape.

  8. Label the sample bottle with identifying information, including case number, date, exhibit number, a brief description including recovery location, and your name. Note the make and model of the vehicle, size and make of engine (for oil analysis tests only), type of fuel used, miles on the engine or transmission, miles on the fluid and filter (since last change). Provide this information to the laboratory when you submit the sample. If some of the information cannot be obtained, gather as much information as possible and submit it. Please note: It is vital that you label each fluid (motor oil, transmission fluid, gasoline, brake fluid, etc.) at the time of collection. Many fluids look similar upon collection.

  9. Store the sample bottle in a secure location until you are able to transport it to the laboratory.

Contact your local laboratory if you have any problems collecting the sample or questions regarding testing.

Laboratory testing of motor vehicle fluids:

Laboratory analyses of motor vehicle fluids can identify the type of fluid present and whether or not any contaminants were present that may hinder the mechanical wear of the vehicle.

Fluid extractor pumps and disposable plastic tubing can be purchased. Many laboratories will provide the bottles for sampling, upon request.

Source:

Stauffer, Eric, and Monica S. Bonfanti. Forensic Investigation of Stolen-Recovered and Other Crime Related Vehicles . Elsevier, 2006: Chapter 11, "Analysis of Vehicular Fluids."

Stauffer, Eric, Julia A. Dolan, and Reta Newman. Fire Debris Analysis. Academic Press, 2007: Chapter 14, pp. 546-558.

Cook, John Lee. Standard Operating Procedures for Collection of Vehicular Fluids. Saddle Brook, NJ: PennWell Publishing Company, 1998.

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