Ignitable Liquid Residue (ILR)
Definition
Petroleum-derived or synthetic liquid accelerant residue surviving in fire debris. Identified by GC-MS against the ASTM E1618 classification system, which groups ILRs into classes by chromatographic profile.
- Source
- Petroleum-derived or synthetic liquid accelerant
- Recovered from
- Fire debris
- Identification method
- GC-MS against ASTM E1618 classification
- Classification basis
- Chromatographic profile grouped into ILR classes
Common questions
Why is it hard to detect ILR in debris from a fire that burned for a long time?+
Extended heat and airflow evaporate the more volatile components of an accelerant, a process called weathering, which can strip away the lighter compounds that make classification easiest. Analysts compensate by targeting the heavier, less volatile compounds that survive longer and by comparing against weathered reference standards.
Does finding ILR in debris automatically prove arson?+
No. Some ignitable liquids are present at a fire scene for innocent reasons, such as stored fuel, cleaning solvents, or building materials that off-gas petroleum-like compounds during combustion. ILR detection is one piece of evidence that investigators weigh alongside burn pattern analysis and scene context.
Related terms
- ATF NCETR
- Bureau of Alcohol, Tobacco, Firearms and Explosives National Center for Explosives Training and Research, based at Redstone Arsenal, Alabama. The US federal...
- BDDS
- Bomb Disposal and Detection Service, operated by state police forces in India. Provides operational post-blast scene management and preliminary evidence collection, with...
- CFSL
- Central Forensic Science Laboratory: a central government lab operating under DFSS. India has CFSLs at New Delhi, Hyderabad, Chandigarh, Kolkata, Pune, Guwahati,...
- DSTL Fort Halstead
- Defence Science and Technology Laboratory site in Kent, UK. The principal institutional capacity for explosives forensic science in the UK, handling major...
- ENFSI EWG
- European Network of Forensic Science Institutes Explosives Working Group. Coordinates best-practice manuals, proficiency testing, and method harmonisation for explosives forensic science across...
- NFPA 921
- US National Fire Protection Association Guide for Fire and Explosion Investigations. The internationally accepted methodology Indian fire investigators and SFSL fire divisions...
- Origin-and-Cause Determination
- The two-part forensic conclusion in fire investigation: the physical location where the fire started (origin) and the mechanism that produced the initial...
- Post-Blast Analysis
- The forensic examination of debris, fragments, and residues recovered from an explosion scene. Aims to characterise the explosive compound, initiator type, device...
- Undetermined (NFPA 921)
- The NFPA 921 conclusion category that records insufficient evidence to establish origin or cause at the 'possible' level or above. Represents the...