Despite there being no investigation report clearing Mwiraria, President Mwai Kibaki appointed him Minister for Environment on 24 July 2007.
Licha ya kuwa hakuna ripoti ya uchunguzi wa kuisafisha Mwiraria, Rais Mwai Kibaki alimteua kuwa Waziri wa Mazingira tarehe 24 Julai 2007.