Duct Cleaning for Fire Safety at Swiftclean

Kitchen Extract System Cleaning If regular duct cleaning is
not
undertaken then greasy deposits left in the ductwork will attract fibrous
build-ups as time progresses, will become baked on, making removal
extremely
difficult and time consuming and creating a fire risk.

[paulmarcell]

I presume the chap washing those filters in the sink lets the water and grease / oil drain out of the sink, into the sewers, causing blockages and damage to water courses?