More than a week after a fire tore through a 116-year-old building in Portland, Ore., what remains of the badly damaged warehouse is causing disruptions and frustrating city officials. “A safety perimeter has been set up around the site to keep the public away from the potential collapse zone,” Dan Douthit, a spokesperson for the city of Portland, said in an email. But Union Pacific, a freight transportation company, resumed operations Tuesday in a decision city officials called a “significant risk to health and safety.” AdvertisingA spokesperson for Union Pacific, Robynn Tysver, said in an email statement that the transportation company was operating, but with limits. According to local news reports, Union Pacific did say it would not ship hazardous cargo past the building until Aug. 21.