A brief overview of the assumed microbial source material of Estonian kukersite kerogen and of the redox conditions in Ordovician epicontinental sea is given. The results of the investigations on the structure and pathways of the phenol formation in the retorting process are analyzed. The distribution of carbon types and oxygen functions are presented, It is concluded that further research into three-dimensional structure, glass-liquid transition and oxygen functions of this aliphatic but oxygen-rich kerogen is needed.