Shropshire Fire & Rescue Service remained on scene at Greenway Polymers – formerly known as Johnson Aggregates & Recycling Ltd, Greenway Waste Recycling and Pink Skips – overnight on Monday and throughout Tuesday.
Dan Quinn, assistant chief fire officer, said work would be ongoing to mitigate the impact of the blaze at the facility on Rock Road for the next seven to 10 days.
Residents in the area are being asked to continue to keep all doors and windows closed.
Mr Quinn said: "We've maintained a presence at the incident overnight, continuing our firefighting to reduce the impact of this serious fire.
"At the moment we have four firefighting appliances and an aerial ladder platform in attendance.
"This work is ongoing and will continue for approximately seven to 10 days.
"In the interim, we're working with our partners from across Shropshire and beyond, so other fire & rescue services such as Staffordshire and Hereford & Worcester are helping us with our activities, and multi agency partners are working with us to minimise the impact – not only on our communities but also the environment and local businesses.
"We appreciate the fire has had an impact on the M54 and the surrounding areas and we thank members of the public for that ongoing support.
"But we continue to ask you to stay away from the area if possible and continue to close all windows and doors."