inflammables

Inflammables are materials that can ignite easily and sustain combustion. The category includes liquids, gases, and some solids. A primary concern is the ignition of vapors; a substance may be non-toxic but still highly flammable if its vapors can reach the ignition source. By contrast, substances that ignite only at very high temperatures are not considered inflammable.

Etymology and usage: Inflammable comes from the Latin inflammare, meaning to set on fire; the prefix in- does not mean "not." Historically, inflammable was widely used in English, but it has caused confusion because its look resembles the negating prefix. Many safety groups now prefer "flammable" and "non-flammable" to avoid misreading, though some labels and older texts still use inflammable.

Safety and regulation: Flammability is assessed by factors such as flash point, autoignition temperature, and flammable limits. Substances with flash points below ambient temperature are particularly hazardous. Preventive measures include eliminating ignition sources, proper ventilation, grounding of containers to prevent static discharge, and storing materials in labeled, fire-resistant cabinets away from oxidizers. Regulatory bodies may require specific labeling and segregation in storage areas. NFPA 704 and other standards provide chemical-specific guidance on flammability hazards.

Examples: Common inflammables include fuels such as gasoline and lighter fluids, solvents like acetone and ethanol, and aerosols. The degree of hazard varies with concentration, temperature, pressure, and enclosure.

Some jurisdictions still use inflammable on signage, but modern practice favors "flammable" to reduce misreadings.