Two workers A & M were working inside the underground pipeline. Due to heavy downpours, both men stopped working leaving the trolley and small portable tools inside. After the rain stopped, these items were submerged in the water. In order to retrieve them, a portable petrol pump was placed inside the pipe to pump water out. Once dried, worker M was asked by his supervisor A to enter the pipe and remove the trolley. Realizing M was too long inside, supervisor A$,$ looked inside and noticed that M was collapsed. He immediately went inside to help but he fell and collapsed. Both men died. Propose system of work to satisfy the section $15(2)($a$)$ OSHA $1994$