A work crew was wrapping the steep tank with poly to protect it against the weather. To do so, the crew was moving the grating away from the tank so that they could slide the poly down and tie it to the tank. While setting down the end of the grating, the injured employee's left fifth finger became caught between the grating and the I-beam. When he went to pull his finger out, he partially severed the fingertip, which had to be surgically amputated.