He replaced Alasdair Hay who had held the role from its establishment in 2013.
However, following allegations of bullying from staff, it is understood that the Mr Blunden was suspended.
Chair of the board, Dr Kirsty Darwent, failed to confirm or deny the allegation against Mr Blunden, but the fire chief’s official Twitter account has also disappeared from the social media website.
She said: “We take any allegation against staff members extremely seriously and have robust procedures in place to ensure complaints are fully investigated.
“Any complaint would be considered confidential while being progressed.”
Mr Blunden was tweeting from the account @FireScot_Chief as recently as March 20 this year, but the account now states that the profile does not exist.
The chief officer role is the most senior professional role at the SFRS and is intended to “provide strategic leadership direction” to the service.
Mr Blunden joined the SFRS following a period of work in South Yorkshire where he was deputy chief officer.
He has also served in Buckinghamshire and Hertfordshire Fire and Rescue Service.
The Scottish Government was contacted for comment.