Since 1998, Mott MacDonald has been providing waste water management for Union Pacific Railroad. In January 2018, a Mott MacDonald employee distracted by a cell phone call left a tank unattended for an hour while working at the railroad's Albina Yard in Portland, Oregon, United States.The tank overflowed and released several thousands gallons of oil into the environment according to US attorneys. 1,800 gallons of the released oil was estimated to have been lost into the Willamette River. The former employee Robert LaRue Webb II was convicted with violating the Clean Water Act in October 2019 and was sentenced to a probation and a fine for negligently causing the oil release. The clean up and emergency response cost the railroad over $500,000. United States Coast Guard, EPA and Oregon Department of Environmental Quality assisted with the clean up.