Richard Matheson from the South Wales Fire and Rescue Service suggests that fire crews dealing with the blaze at the Vale Business Park may be on site for days.
The "deep-seated" fire involves a large amount of mixed recycling materials.
One of the owners of a soft furnishings business in the area was notified about the fire by one of her employees after they saw smoke from one of the buildings nearby.
Pam Owen, owner of Pam Owen's Soft Furnishings, has been in business for more than 25 years and is worried about the fire spreading.
More top news
Martin Tate taunted North Wales Police via a Facebook appeal for him by saying "see who has the last laugh now".
The 25-year-old, known locally as Bilal, was arrested on Tuesday in Newport. Two men were also arrested the following morning in the city.
Simon Wilson successfully blagged his way into the Emmy Awards, just a month after gaining entry to the McGregor v Mayweather boxing fight.