On 2-25-04 ee strained lower back as he was pulling on a wrench while taking apart a pump in the Prep Plant. Injury was treated as 1st aid case. On 5-6-04 ee informed Safety Dept he was having reoccurring problems from the injury that occurred on 2-25-04. He was taken to Center for Occupational Health & examined. He was diagnosed w/lumbar strain & instructed to go to Phys Therapy