Hundreds of University of Minnesota students were evacuated and nearby stores shut down Tuesday afternoon while authorities investigated the report of a suspected haz­ard­ous substance near campus.

The evacuations were in the 500 block of 14th Avenue SE. in Dinkytown, a popular area for off-campus housing and bars and restaurants. The case involves an “unconfirmed report of ricin,” a danger­ously toxic sub­stan­ce found in castor beans, the Minneapolis Fire Department tweeted.

Assistant Fire Chief Brian Tyner said the substance was contained to one apartment. The resident took herself to the hospital before fire crews arrived.

Residents were allowed to return to the building five hours after the evacuations began. A guard was stationed at the affected apartment overnight.

The Police Department took over the investigation, announcing late Tuesday that a hazardous-materials team had “secured the substance” and sent it to a lab for analysis. A rush was put on the order, but authorities say they are unsure when identification would be confirmed.

Until that time, the area will be treated like a potential crime scene, said police spokesman John Elder. The woman who was hospitalized is expected to be OK, he said.

Fire crews arrived about 4:20 p.m. and ev­acu­at­ed The Marshall, an apartment complex that caters to students, and connecting addresses while sealing off the af­fect­ed area. The large building faces multiple streets and has several street-level retail outlets, including a Target Express that was closed.

Dozens of students stood aimlessly behind yellow police tape or lounged on the grass across the street as they awaited word that they could get back into their apartments. One bit of good news: The property owner was picking up the tab for students’ dinners at Blarney Pub and Grill before 9 p.m.

Seniors Jason Cook and Tyler Baumann sipped beers and munched bar food on the patio as they debated whether to call their parents. “We’ll be chilling here for awhile,” Cook said as the sunset neared. “This isn’t a bad way to pass the time.”

‘Kinda scary’

Betsy Ettinger had driven past all the commotion and made it into The Marshall’s parking garage shortly before 5 p.m. without knowing what happened. She walked up to an empty dorm and was greeted by a knock on the door. A man in a hazmat suit appeared, demanding that she evacuate for her safety.

“It was kinda scary,” the junior said. “Now we’re going to sit here until it’s over because we have nowhere else to go.”

Her roommates were in the same boat.

“It’s too bad it’s in the middle of finals,” said junior Elli Vesely. “A lot people probably need their study materials and are super stressed out right now.”

University student Jacob Lawson said that as firefighters left the building, they were washed down by a portable shower before taking off some of their heavier equipment, he said.

Student Laura Buscheck grabbed her dog and ran outside with her roommate when the alarm sounded. “We don’t have a plan,” she said, before residents were allowed to return. “We don’t know where we’re going to sleep tonight.”