A total of 10 fire engines were at the scene at the peak, with an aerial ladder platform and two special units - a water support and incident command unit - also on site.
The blaze broke out at Priory Tech Park in Hessle on Wednesday afternoon.
Jason Kirby, Director of People and Development at Humberside Fire and Rescue Service, said “Our firefighters are continuing to make good progress to tackle the fire.
"Our multi-agency partners are working with us to resolve the incident and these include Humberside Police, UK Health Security Agency and Environment Agency who are working with us to minimise any impact on the environment.
"Local residents may notice low water pressure and possible discoloration, and this is because local water authorities are diverting water for the incident, please do not be alarmed if you experience this with your water supply.
“Residents in areas affected by the smoke should stay indoors, keep their doors and windows closed, and check for updates on our twitter feed @HumbersideFire.”
Drivers are advised to avoid the area and take care if they are driving nearby on the A63, and should keep windows closed, turn off air conditioning and keep their air vents closed.
Grace Grant, 25, said she heard explosions coming from the fire.
“It was huge, smoke could be seen from miles away. As I moved off, explosions were happening around every 10 seconds”, she said.
Local pubs in the area said they would offer free drinks to those affected by the fire.
The Fiveways posted to Facebook saying: “We are happy to provide free hot drinks & shelter to those affected by the fire in Hessle. Free hot drinks to emergency workers.”
Another pub, The Norland, posted: “We are aware that a number of locals have no power so we will remain open for drinkers free tea and coffee available.”
Humberside Police cordoned off Priory Way with Saxon Way, Hull Road with Hessle Road roundabout, Hull Road with Buttfield Road and Ferry Road, but are now beginning to reopen them.
There is also no foot access over Livingstone Road foot bridge.