The fire broke out at Skip It Waste Site in College Road at around 10.30pm yesterday (June 25).
Officers and Kent Fire Rescue Service attended and found several lorries that were on fire.
The blaze was put under control shortly after.
Road closures remain in place at the junctions with Longdown Lane and Reigate Road.
Officers are urging residents to avoid the area while emergency services deal with the incident..
A spokesperson for Surrey Police confirmed that it is believed that the fire was started deliberately.
No injuries were reported following the incident.
Epsom and Ewell Borough Commander, Inspector Tommy Pearson said: “We received several reports of large explosions last night and I know this will have caused serious concern within the community.
“I would like to reassure residents that we are investigating thoroughly to establish the circumstances and find those responsible.
“If you have any information, I urge you to get in touch with the police.
“We would like to speak to anyone with information that can support our investigation. If you were in the area of College Road last night around 10:30pm or if you have any dashcam, doorbell or CCTV footage that could assist us, please contact us quoting reference number PR/45250076857.
“If you do not wish to speak to police, you can also contact independent charity Crimestoppers on 0800 555 111.”
