A California woman is waging a personal battle to raise awareness about the dangers of certain swimming pool filters following the death of her husband. Jim Halverson suffered fatal injuries when his pool’s two-piece, kettle style filter exploded and struck him in the head. Attorneys and other consumer advocates argue that a design flaw in the kettle-style or canister filters can make them extremely dangerous. At least 22 similar incidents and four deaths have been attributed to the filters since 1982, according the Consumer Product Safety Commission.