Fluorescent light bulbs (CFLs) — breakage and mercury vapor — household safety profile

What is this product?

Compact fluorescent light bulbs (CFLs) contain elemental mercury sealed within the glass tube — mercury is not a contaminant in CFLs but a functional component essential to the ultraviolet light generation mechanism of fluorescent lamps. Each CFL typically contains 3–5 mg of mercury. When intact and functioning, CFLs are safe to use; the mercury is sealed and does not escape into the environment during normal operation. The hazard materializes when a CFL breaks: the sealed mercury is released as mercury vapor (the vapor pressure of elemental mercury at room temperature is sufficient to generate airborne concentrations that significantly exceed health reference values in a poorly ventilated room) and as mercury-containing phosphor powder coating the interior of the glass tube. The EPA cleanup protocol for broken CFLs — developed in 2013 guidance — specifies a counterintuitive set of actions that most consumers don't know: evacuate the room for at least 15 minutes and ventilate through open windows before cleanup; do NOT vacuum — vacuuming disperses mercury vapor and permanently contaminates the vacuum cleaner; scoop glass fragments and powder with stiff paper or cardboard; seal in a glass jar or two sealed plastic bags; wipe the area with a damp paper towel (not dry cloth); dispose as hazardous waste. The HVAC contamination scenario is a distinct and underrecognized hazard: if a CFL breaks near a cold-air return vent or while the HVAC system is actively circulating air, mercury vapor can be distributed throughout the home's duct system and into multiple rooms simultaneously. HVAC duct decontamination is expensive, technically difficult, and has resulted in costly whole-home remediation in documented cases. The LED transition is essentially complete in the US market: LED bulbs now provide equivalent or superior light output at equal or lower wattage, with 10–25 year lifespans, zero mercury content, and lower energy consumption. CFL manufacturing has largely ended. However, the existing installed base of CFLs in homes, offices, and commercial buildings represents a continuing breakage hazard for years as these bulbs reach end of life.

What's in it

Click any compound name for its full safety profile, regulatory consensus, and exposure data.

Who's most at risk

• Children — Developing endocrine and neurological systems, higher exposure per body weight

How to use it more safely

• Use in well-ventilated areas away from occupied spaces
• Install in fixtures with protective covers or enclosures
• Handle with care to prevent bulb breakage
• Keep away from children and pets

Red flags — when to walk away

• Broken CFL in a room — vacuuming up the fragments, remaining in room without ventilating, or breaking near an HVAC return vent while system is operating — Vacuuming broken CFL disperses mercury vapor through the vacuum exhaust and permanently contaminates the vacuum with mercury — this is one of the most counterintuitive but important CFL safety facts. Remaining in a room without ventilating after a CFL breaks exposes occupants to elevated mercury vapor concentrations. Breaking a CFL near an active HVAC return can distribute mercury vapor throughout the ductwork to multiple rooms.
• CFLs disposed in regular household trash — not recycled through appropriate hazardous waste channels — CFLs in regular trash risk breakage in the trash can, during collection vehicle compaction, or at the landfill — releasing mercury to the environment. In most US states, disposing CFLs in regular trash is illegal. Even in states without explicit prohibition, the mercury content makes CFL disposal a regulated waste stream.

Green flags — what to look for

• LED bulbs replacing CFLs throughout the home; no CFL breakage in household history; CFLs in use handled with care and recycled at end of life — LED bulbs eliminate the mercury vapor breakage hazard entirely. The LED transition in the US market is essentially complete — new bulb purchases should be LED. For homes with existing CFLs: they can continue in service to end of life (no safety benefit from early removal, and handling increases breakage risk). Handle CFLs like what they are: glass tubes containing mercury. Recycle properly at end of life.

Safer alternatives

• LED bulbs — No mercury, durable, longer lifespan, lower breakage risk
• Incandescent bulbs (phased out) — No mercury vapor risk but less energy efficient

Frequently asked questions