EE was walking around fueling station to do some clean-up & twisted his right ankle. He said no specific cause & the ground was level. Our Safety Director spoke with a Coder at MSHA Office of Injury & Employment Information on 4/6/06 about incident & was told it would not be reportable. Site was inspected on 4/25/06 & MSHA Inspector told Plant Manager that 7000-1 must be completed.