A company spokesperson said the plant was expected to resume normal operations on Friday.
Billowing black smoke could be seen over parts of downtown on Wednesday.
The interstate is blocked between Dumesnil Street and Cane Run Road, near the Park DuValle neighborhood.
Crews were called to a warehouse off Cane Run Road about 6:30 a.m. Thursday.
The restrictions on I-75 north of I-275, including on the Brent Spence Bridge, aren't known by major trucking associations in Kentucky and Ohio. There is no signage notifying drivers in Kentucky, state officials have confirmed.
MetroSafe says high-levels of CO or carbon monoxide were reported in the area.
More than 100 emergency responders from southern Indiana and the government gathered to discuss proper protocol for life-threatening hazmat situations.
The leak was reported around 4 p.m. on Wilson Parkway, which is just off of New Shepherdsville Road, according to the Bardstown Fire chief.
Residents in the Ghent area were asked to remain indoors until the advisory was lifted around 8 a.m.