Definition & Operational Usage of Xylene
What Is Xylene?
Xylene (dimethylbenzene) is a flammable, colorless aromatic hydrocarbon solvent (UN 1307, Flash Point 81°F / 27°C, Vapor Density 3.7) that presents severe fire hazards, narcotic central nervous system depression, and respiratory irritation upon exposure.
⚠️ Operational Safety Warning:Xylene vapors settle in low areas and ignite easily. Eliminate all ignition sources and apply Class B foam for vapor suppression.
Why Xylene Matters on the Fireground
Xylene vapors are 3.7 times heavier than air, pooling in basements, pits, and sewers to create explosive atmospheres. Responders require Level B PPE with SCBA and non-sparking tools for spill containment.
Relevant NFPA Standards
- NFPA 470: Hazardous Materials/Weapons of Mass Destruction (WMD) Standard for Responders
- OSHA 29 CFR 1910.120: Hazardous Waste Operations and Emergency Response (HAZWOPER)
Field Procedures & Tactical Steps
- Consult DOT ERG Guide 130 (Flammable Liquids - Water-Immiscible).
- Approach scene upwind with Level B PPE and positive-pressure SCBA.
- Monitor atmospheric LEL and toxic vapor levels (IDLH = 900 ppm).
- Apply Alcohol-Resistant AFFF (AR-AFFF) foam blanket over liquid spill to suppress flammable vapors.
- Dike liquid runoff using non-sparking shovels and absorbent booms.
Common Context & Application
Encountered in paint manufacturing, chemical transport spills, industrial solvent leaks, and fuel blending operations.
Frequently Asked Questions about Xylene
What is the IDLH threshold for Xylene?
The NIOSH IDLH threshold for Xylene is 900 ppm based on severe central nervous system depression and respiratory toxicity.
Why is Class B foam required for Xylene spills?
Xylene floats on water and releases flammable vapors; Class B foam forms a blanket over the liquid surface, suppressing vapor release and preventing ignition.
Other Names for Xylene
dimethylbenzenexylol
Xylene may also appear in training materials, NFPA standards, or department SOPs as: dimethylbenzene, xylol.
Relevant Tools
Operational calculators related to Xylene:
Category:Hazmat & CBRN
— Hazardous materials, decon, isolation zones, UN/ERG concepts, and CBRN terminology.