ROUND ROCK, Texas (KXAN) — The northbound lanes of Interstate 35 at Old Settlers Boulevard in Round Rock, previously shut down Monday afternoon and evening, are now starting to reopen.

As of 9:30 p.m., Round Rock police say the lanes are reopening as hazmat crews clean up oil left behind from a wreck involving an 18-wheeler.

Originally, cleanup was thought to take about an hour, but at 5:55 p.m., the lanes remained closed.

In a 7:40 p.m. update, police say one lane was reopened. While the 18-wheeler was removed from the road, crews were still trying to clean up the oil.