Why is it risky?
Burning paraffin candles releases volatile organic compounds (VOCs) and soot. Essential oil-based candles and reed diffusers release higher concentrations of terpenes and aromatic compounds. Cats have highly sensitive respiratory systems and limited ability to metabolize many aromatic compounds via glucuronidation. Risk scales with fragrance concentration, room size, and ventilation.
Affected Systems
Liver · Respiratory
Symptoms
Watery eyes, sneezing, coughing, lethargy, respiratory irritation. Essential oil candles with prolonged exposure: additional hepatic stress symptoms.
What To Do
If a cat shows symptoms after candle use: move to fresh air. If symptoms persist beyond 30 minutes: vet visit.
Notes
Cats confined to indoor environments cannot self-limit exposure. Soy or beeswax candles with minimal synthetic fragrance are safer than heavily scented paraffin candles. Essential oil diffusers, particularly ultrasonic diffusers that aerosolize the oil, present higher risk than candles and should be used with extreme caution around cats. A diffuser with eucalyptus or tea tree oil in a closed room is a genuine hazard.
Sources
→ International Cat Care — icatcare.org
→ ASPCA Animal Poison Control Center — aspca.org