Table schema:
CREATE TABLE table_name_66 (date VARCHAR, location VARCHAR, casualties VARCHAR, circumstances VARCHAR)

Question: When was the location 15km NW of Pol-E Khomri, the circumstaances IED and the casualties of 1 WIA?
SQL: SELECT date FROM table_name_66 WHERE casualties = "1 wia" AND circumstances = "ied" AND location = "15km nw of pol-e khomri"