The blaze at BCB Environmental Management on the Marston Moor Business Park in Tockwith, near York, destroyed the waste transfer station and was tackled by 40 firefighters.
Yesterday, it was revealed that the firm's directors had filed a notice to appoint Christopher White and John Russell of The P&A Partnership in Sheffield as joint administrators.
A statement issued on behalf of the administrators, said: "On August 11, the company's trading premises were destroyed by a fire causing an environmental risk to the surrounding areas.
"The Environment Agency served an anti-pollution works notice on the company on August 16. This required certain works to be undertaken to help safeguard the neighbouring Fleet Beck.
"This work is ongoing in close liaison with the Environment Agency. Prior to the joint administrators' appointment, the company had laid off 33 of its 37 staff. These employees were formally made redundant upon the joint administrators' appointment."
An Environment Agency spokesman said yesterday: "The fire is out but the waste continues to smoulder. We have made the administrator fully aware of the serious nature of this incident and the need to clean up the site."
The Health and Safety Executive has begun a formal investigation.