An unidentified chemical spill was reported at Engineering Hall today at 12:15 p.m. The University of Wisconsin Police Department responded along with the Madison Fire Department to the investigate the call.

UWPD spokesperson Marc Lovicott said the fire department is the lead agency on the scene, and they are bringing in their Hazardous Materials Unit to assess the situation.

Lovicott said authorities are still in the process of investigating what chemical was spilled and what caused the incident but have evacuated Engineering Hall along with traffic on Engineering Drive as a safety precaution.

“We’re asking folks to avoid that area because there’s a lot of trucks and congestion,” he said.

Lovicott said more information will be released as officials .

Update 1 (1:20 p.m.): UWPD is now reporting the chemical leak has been contained and Engineering Hall is safe to re-enter.

Engineering Hall update: building has reopened. Chemical leak is contained and was minor and not hazardous. All is well now at Engineering.

— UW-Madison Police (@UWMadisonPolice) February 27, 2014

Update 2 (1:50 p.m.): Lovicott said the spill occurred during a filter replacement on a tank when a small amount of the hazardous chemical arsine leaked out. He said although the spill triggered the alarm, the arsine leakage does occasionally happen with such filter replacements.

“It turns out the leak was contained, and there really wasn’t a hazard,” Lovicott said. “The building was evacuated just as a precaution so we could figure out what exactly happened and how much leaked.”

As of now the building has been deemed safe and has reopened, Lovicott said.

[Photo via UW Junior Max Schweiner]