While positioning the stack test cap, the attached sling separated at the swage. The eye of the sling was coated with plastic and crimped into the swage. This sling had been included in a lifting survey completed in June 2003. The sling was rated for 5 tons and parted at 2 tons. Due to the load being controlled, rather than a free load, the cap was unable to fall any distance and no injuries were sustained.