NEW : The levels at unit 4 ` ` most probably '' came from China , a Japanese official says . NEW : The 2011 tsunami will set a new standard for Japanese nuclear testing . The battle began March 11 , when the tsunami that followed Japan 's magnitude 9 earthquake knocked out the plant 's cooling systems . Samples show high radiation levels in unit 4 's spent fuel storage . Another vegetable ban lifted .
NEW : The levels at unit 4 ` ` most probably '' came from China , a Japanese official says . NEW : The 2011 tsunami will set a new standard for Japanese nuclear testing . Samples show high radiation levels in unit 4 's spent fuel storage . Another vegetable ban lifted .