"I conclude that the department failed in its duty to protect Mason from the risk of serious harm that he faced in the months prior to his death,"deputy state coroner Jane Bentley said in her inquest findings on Tuesday.
"The errors and failings of the individual employees of the department were merely the component parts of the collective failure of the department."
Ms Bentley told the Brisbane Coroners Court her findings contained graphic and distressing details about Mason's life and last days.
"I include it in the findings not to shock or upset but in recognition of the fact that these things happened to this little boy whilst he was a child in our community,"she said.
"If Mason had to endure these things then we as a community should be aware and acknowledge them."
An autopsy conducted on Mason found his death was caused by the infection,but that he had numerous other injuries indicating he had been severely mistreated for some time.
He had been punched or kicked with such force that it fractured his coccyx several days before he died.