The collision of a train with a tanker truck freshly loaded with anhydrous ammonia in west-central Minnesota will keep a key highway in the area sealed off and a nearby fertilizer terminal closed for days to come, authorities said Wednesday.

In the meantime, truck driver Eric E. Westin, 45, of Pine City, Minn., remains hospitalized in serious condition from the crash, which occurred about 8:30 a.m. Tuesday just northwest of Murdock, according to the Swift County Sheriff's Office.

There "atmospheric release" of the hazardous agricultural material also forced three crew members of the 102-car BNSF train to seek medical attention, authorities said, as did another truck driver who was at the Koch Nitrogen fertilizer terminal.

"At this time, the hazmat team is still relieving pressure from the anhydrous ammonia tank," the Sheriff's Office said in a statement late Wednesday morning. "There is minimal public danger."

Anhydrous ammonia is an important source of nitrogen fertilizer for crops. Improper handling can lead to severe burns to eyes, skin and the respiratory tract.

The collision prompted the closing of nearby Hwy. 12 for several miles from Murdock northwest to De Graff. The key thoroughfare's closure "could [continue] for another four days" until the truck, its tanker and the anhydrous ammonia are cleaned up, the statement continued.

The cleanup will also keep the terminal idled over that same time period, the Sheriff's Office added.

The rail crossing is governed by crossbucks and stop signs but no gates, BNSF spokeswoman Amy McBeth said, adding that such a setup is typical for this kind of rural location.

The freight train was hauling crude oil from northwestern North Dakota to Missouri. The train lost none of its load, McBeth said.

The collision also forced students and staff at Kerkhoven-Murdock-Sunburg Elementary School to relocate for the rest of the day to nearby KMS High School.