SANDY — Sandy City released a computer simulation Thursday showing how they believe fluoride traveled through their water system earlier this month.The animation shows the highest levels traveling through the areas the city later deemed zones one and two. The fluoride levels in those areas exceeded 10 milligrams per liter, which Sandy Public Utilities engineering manager Richard Benham said was the level at which the Centers for Disease Control and Prevention requires water systems to shut down their fluoride equipment.

City officials have said the high concentrations of fluoride in that area increased the acidity of the water and let copper and lead in the pipes of some homes leach into their water. They said the lead and copper were not found in the city’s water supply.

Elevated levels of fluoride also flowed through zone three, but the computer model predicted those levels were below 10 milligrams per liter. The model showed a brief spike in those areas, but Benham said those readings were likely outliers.

The city asked volunteers to help them gather samples from each house in the affected area to determine whether there are any lingering effects.

The city is also commissioning an independent investigation into what happened. During that investigation, Sandy City Public Utilities director Tom Ward is on paid administrative leave.