One tanker carrying crude oil was badly listing and three others were off the track Friday after a morning derailment on the west end of Montana Rail Link’s Missoula yard.

“So far it doesn’t appear anything leaked, but they’re going to keep a close eye on it when they move it,” Michelle Hutchins of the city-county health department’s Missoula Valley Water Quality District said at midafternoon.

Hutchins said the derailed oil tankers are of the newly designed variety, built stronger and with other safety technology incorporated.

“So that seems to have done its job,” she said.

The low-speed derailment happened at around 8:30 a.m. Friday. Montana Rail Link’s Jim Lewis said the cars were part of a westbound loaded crude train that was leaving the yard. There were no injuries and no hazardous materials were released. The cause of the incident is under investigation.

“Mainline traffic has not been interrupted and MRL haz-mat and mechanical experts are supervising the re-railing process, which is expected to be completed by Friday evening,” Lewis said in an email at 4:45 p.m. “Local, state and federal agencies were notified per standard protocol.”

The derailment occurred on tracks closest to West Broadway, a few hundred feet east of the Reserve Street overpass.

It’s in the same area where 30 empty tank cars derailed in December 2014 in a switching snafu, after a loaded car made low-speed contact with one of them. [Ed. – see back stories here.]

Last December a coupling broke in the pump house at MRL’s west refueling station near Zootown Arts Community Center. Some 7,000 gallons of diesel fuel poured out before the break was discovered and the valve turned off.