Grease build‐up in steam vent causes fire in Courtenay bakery

Incident Investigation

Grease build‐up in steam vent causes fire in Courtenay bakery

March 27, 2017


Reference Number:


Incident overview

Rotating rack bakery oven had a grease fire in the steam venting which resulted in nearby trusses catching fire.

Regulated industry sector

Gas/ natural gas



Investigation conclusions

Site, system and components

Rotating rack oven used for backing bread has been used for 10 plus years without the steam system. With steam system never being used, steam vent should remain closed during baking cycle. They have been baking all this time with steam vent open which likely caused a slow buildup of grease in the steam vent, which caught fire in the vent(which is single wall “C”vent), resulting in the nearby trusses catching fire.

Failure scenario(s)

Build‐up of grease in steam vent caught fire due to vent being operated in “open” position and heat from baking cycle igniting the grease. The heat from prolonged use with vent open likely caused pyrolysis of the wood trusses which were more easily ignited during the grease fire in vent.

Facts and evidence

Evidence of excessive heat from fire in steam vent and roof termination as seen in photos. Neighbor witness also saw flames shooting from vent.


  • Injury
    • Qty injuries: None
    • Injury description: None
    • Injury rating: None
  • Damage
    • Damage description: Moderate burn damage to trusses and roof. No damage to equipment
    • Damage rating: Moderate

Incident rating



116.83 KB