HOUSTON (CBSDFW.COM/AP) — Agents with the FBI in Houston have arrested a teenager after dozens of people were decontaminated as a precaution due to trace amounts of mercury spilled at three locations across the city.

On Twitter, the Houston office of the FBI said Christopher Lee Melder, 19, has been arrested and charged with burglary and unlawful disposal of hazardous material.

Houston Fire Chief Sam Pena said at a news conference Sunday evening that the situation was under control and crews were cleaning up the spills. There’s no timetable for when the cleanup will be complete.

Someone called 911 around 11:15 a.m. Sunday to report a white liquid on the ground, Pena said. Officials later determined that mercury was spilled outside a Walmart, a Sonic Drive-In and a nearby gas station. All three locations were evacuated and between 30 and 60 people were asked to take decontamination showers as a precaution, Pena said.

The fire chief added that one woman was taken to a hospital as a precaution because she was pregnant.

(credit: CBSDFW.COM)

According to the Centers for Disease Control and Prevention, mercury exists in three forms. Elemental mercury is liquid at room temperature. It is used in some thermometers, fluorescent light bulbs and electrical switches. High mercury vapor concentrations can cause severe lung damage, the CDC said.

Dr. David Persse with the Houston Health Department said that because all three spills happened outdoors, the risk to people in the area is minimal.

(© Copyright 2019 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)