Design requirements for forensic laboratories are unique and unlike those for other laboratory types. While forensic labs share certain features with academic, research, and other laboratories, the composition of these elements and the addition of other characteristics make these facilities an uncommon challenge. Seven general criteria underscore how different forensic facilities are from other laboratories:
- Lab section organizational structure
- Interaction/collaboration requirements
- Five-in-one laboratory structure
- Unique laboratory sections
- Unique mission
- Chain of custody requirements
Lab section organizational structure
A forensic laboratory consists of a number of separate and distinct laboratories, each with its own specific function, spaces, and equipment. For accreditation purposes, each laboratory section must be designed as a separate and secure entity. Although different crime labs will likely not have identical organizational structures, some typical forensic laboratory sections include:
- Biology section—for the examination of biological evidence and the development of DNA profiles. This section must be designed as a biological sciences laboratory and is also responsible for assisting in the maintenance of an international DNA database.
- Chemistry section—usually for the examination of narcotics, narcotics paraphernalia, and other forensic examinations involving wet chemistry procedures. This section also relies on substantial numbers of instrumentation units, such as GC/MSs, FTIRs, ICP/MSs, and other computer-driven, diagnostic instrumentation.
- Toxicology section—for the examination of blood and urine for the presence of drugs, alcohol, or other foreign substances. This section frequently provides laboratory support for medical examiners by examining tissue samples from decedents in order to determine cause of death, and it must be designed to include features of wet chemistry and biological sciences laboratories. Like the chemistry section, the toxicology section uses various types of gas-consuming, heatgenerating, noise-producing instrumentation requiring isolation and special design considerations.
- Latent fingerprint section—for the examination of evidence for the presence of fingerprints, using various chemical and nonchemical procedures. Responsibilities also include fingerprint input and searches in an international fingerprint database.
- Firearms section—for the examination of any evidence pertaining to firearms, including weapons, bullets, bullet projectiles, and bullet casings. This is primarily a physical properties analysis laboratory, but does include some elements of a wet chemistry lab. This section also includes instruments designed to access an international database of bullet components.
- Trace evidence section—for the identification of any substances that cannot be identified in the chemistry section. Typical substances include microscopic particles known as trace evidence and can include, but are not limited to, paints, glass, food products, and building products. This section relies heavily on instrumentation and microscopy, including scanning electron microscopes, FTIR microscopes, and comparison microscopes.
These are just a few examples of the laboratory section organizational structure of a crime lab. Other spaces within a crime lab might include an arson examination lab, a forensic garage for the processing of impounded vehicles, and a questioned documents lab for the examination of any evidence that includes paper, inks, and forged documents.
Most laboratories encourage interaction and collaboration among their scientists, analysts, and technicians; however, in a forensic laboratory, it is essential that the forensic staff have dedicated spaces for interactive activities. It is not uncommon that an item of evidence must be examined in two or more laboratory sections. A pistol submitted as evidence, for example, might contain blood stains, which immediately necessitates the examination of this pistol in three laboratory sections: firearms, biology, and latent fingerprints. Inviting and comfortable interaction spaces should be provided to encourage forensic scientists to engage in informal conversations to discuss cases and explore strategies.
Five-in-one laboratory structure
There are five basic laboratory types in terms of their architectural and engineering design requirements: wet chemistry, biological sciences, instrumentation, microscopy, and physical properties analysis. Most laboratories contain two to four of these laboratory types; however, forensic laboratories are unique in that they consistently employ all five of these laboratory types within the same facility.
Wet-chemistry laboratories are spaces designed for the handling of hazardous chemicals. To mitigate these hazards, these laboratories utilize fume hoods and other specialty containment devices. While most sections within a forensic laboratory have some degree of wet chemistry, the toxicology, drug chemistry, and biology sections are typically the most chemical-intensive. Biological science laboratories are those that examine biological specimens or evidence, which may be infectious or highly prone to cross-contamination. In forensic laboratories, procedures for DNA profiling are undertaken in this type of laboratory. Many other laboratory sections in the forensic lab, including the blood alcohol and latent prints sections, deal with biological evidence.
Instrumentation laboratories are those designed to house a concentrated number of pieces of computer-driven analytical equipment. It is not uncommon for many non-forensic laboratories to have a GC/MS or two at the end of a laboratory bench; however, forensic laboratories typically contain large numbers of these heat-generating, noise-producing, and gas-consuming instruments. In the Center for Forensic Science laboratory, currently being designed in Toronto, the toxicology section alone will have space for 80 of these instruments. Each laboratory instrument comes with a unique set of requirements for utilities, vibration, countertop or floor area, environmental conditions and exhaust. The drug chemistry, trace evidence and toxicology sections utilize the majority of instrumentation in a forensic laboratory.
Benchtop microscopy at laboratory workstations is not uncommon for most laboratories. In addition to more common microscopy, the forensic laboratory will contain specific rooms designed for substantial numbers of sensitive microscopes. Equipment types will include stereo and polarizing microscopes, FTIR microscopes and comparison microscopes. The trace evidence section of the crime lab will typically require a specially designed room with light control for varied microscopy, in addition to a scanning electron microscope room with its detailed requirements.
Physical properties analysis laboratories are those that disassemble and physically analyze the parts and components of particular items of evidence. These types of laboratory sections have specific requirements for layout space and specialized casework, as well as for storage of reference materials and comparison exemplars. Special consideration must be given to the type of items being analyzed as well as to their physical and utility requirements in order to provide an optimal environment for the analytical process. Examples of these types of laboratory spaces in the crime lab include the firearms, forensic garage and digital forensics sections.
Unique laboratory sections
While forensic laboratories have several sections in common with laboratories in general, what really set these facilities apart are their unique sections. Examples include sections for firearms examinations, which include a firing range and bullet recovery tank; questioned documents, with specialized equipment designed for document examination, such as electrostatic detection apparatus and visual spectral comparators; latent prints, which includes unique procedures and equipment using cyanoacrylate (superglue), powder dusting, alternate light sources, and volatile chemical processing; and vehicle examination, or a forensic garage, for the processing of impounded vehicles for fingerprints and trace evidence.
At its essence, the forensic laboratory is dedicated to diagnostic analysis. No other laboratory type is consigned to discovering the who, what, when, where, why, and how of forensic evidence. From humble beginnings and limited resources, the field of forensic science has ascended to become an indispensible tool internationally in the fight against crime. The unique steps that comprise the forensic mission include crime scene processing, collecting of forensic evidence, providing scientific examination of forensic evidence, and providing testimony in a court of law regarding the findings.
Spurred by the National Academy of Sciences report on the state of forensic science in the United States, U.S. District Court Judge Nancy Gartner recently urged defense attorneys to challenge the basis of analysis for evidence submitted and prosecutors to defend its validity.1 These types of increasing pressures will drive the field to continual refinement of accepted processes, protocols, and procedures, which, in turn will have significant implications for the manner in which forensic laboratories are designed.
Chain of custody requirements
An important component of ensuring the validity of test results is the proper handling of forensic evidence throughout the investigation process. From the time that evidence is collected at the crime scene until it is presented in a court of law, it is crucial that the sometimes rigorous, court-mandated requirements for chain of custody of evidence are met. For the forensic laboratory this means that evidence must be accurately accounted for as to its location, who has handled the evidence, and which individual has custody of the evidence through each step in its journey. The facility must be able to not only accommodate a means of continuous document tracking, but also must provide an accepted secure means of housing evidence at proper environmental conditions at all times. If a defense attorney can prove that a continuous chain of custody of evidence has been broken, that evidence will be inadmissible in court.
While the forensic laboratory shares many characteristics with its laboratory brethren, its many unique characteristics demand a specific set of facility design responses. Advances in technology, increased scrutiny, developing techniques, and refinement of procedures are certain to continue to change the parameters required to effectively undertake forensic investigations. Documents such as the National Academy of Sciences report have irrevocably diverted the future of forensic science. With so many influences, forensic laboratory design will continue to evolve to meet the investigative necessities of tomorrow.
- Jonathan Saltzman, “U.S. Judge Urges Skepticism on Forensic Evidence,” The Boston Globe (March 29, 2010).
- 2. ASCLD-LAB, “History of the American Society of Crime Laboratory Directors Laboratory Accreditation Board (ASCLD/LAB),” http://www.ascld-lab.org/about_us/history.html.