The canister is hopeless overfilled. Action has been needed much earlier!
The canister is placed next to a sink. The spilled waste is found 1 cm in front of the sink. In other words: It is just this single centimeter, which is separating you from a criminal charge by the envionmental agency - if they find out what has happened.
Solvent waste canisters have to be stored safely. Put them into a trough or a bucket so that spilled content cannot run into the sink.
But what to do with the overfilled cannister??