Four workers suffered burns and were taken to a local hospital, another worker fell as he operated a fire hose during the emergency response.
Pemex said in a statement that firefighters had controlled Tuesday's blaze at the Antonio Dovali Jaime refinery in the southern state of Oaxaca.
'I am burning!' screamed one victim.
Officials think the drug lord injured a leg and his face in evading capture.
Pope Francis sent a note of condolences Friday to the families of the victims.
The eight workers are being treated for possible injuries due to fumes.