Hundreds of factory workers have been evacuated and at least five hospitalised after a chemical spill at an Ipswich workplace, west of Brisbane.Emergency services were called to JBS Dinmore after a liquid ammonia spill occurred at the facility about 12:30am.Almost 900 people were evacuated and 17 have been assessed by paramedics.Five people were taken to hospital in a stable condition.The fire department said it has stopped the leak but crews remain on scene.JBS Dinmore is one of the largest employers in the Ipswich region. It's also one of the largest beef processing plants in the southern hemisphere.JBS and Workplace Health and Safety Queensland have both been contacted for comment.