Answer:
Benefit : Easier access to Natural gas
The pipeline made it much more easier to transport natural gas from its mining point in Prudhoe Bay, North Alaska to the areas where it was be needed by the residents of Alaska.
Risk: Environmental damage
Transporting oil always come with the risk that there could be a spill or leak for a myriad of reasons. Should this happen with the pipeline, vulnerable flora and fauna could be lost in the ensuing destruction that would be wreaked on the environment.