It happened on Route 3 near East Valley Road around 9 a.m. but the large mess left behind will likely take a while to be cleaned up.
Route 3 was closed in both directions following the crash, but the westbound lanes reopened Monday evening.
Eastbound lanes are still closed between Route 46 and Grove Street. One eastbound lane is expected to reopen Thursday night, and the remaining three lanes will remain closed until 5 a.m. on Tuesday, according to officials.
The fire chief said the crash happened when the box truck and a New Jersey Transit bus collided. The truck then exploded when it crashed through the sound barrier into the back yard of several houses.
"I felt three explosions in my house. I thought it might have been an earthquake again," said Clifton resident Mary Ann Zimmerman.
The truck apparently had signs saying it was carrying a corrosive, but it is not yet clear what the chemical was.
"The truck had placards on it, from the best that we could determine, that said it was carrying corrosive and explosive chemicals," Clifton Fire Department Acting Chief Daniel Collins said.
The body of the 55-year-old driver was discovered after the fire was brought under control. There were 29 customers on the bus, but everyone on board is said to be OK.
"I kind of just thank God that the bus kept going forward. Because if we hadn't, and we were adjacent to the truck, could be a different story," said NJ Transit passenger Tom Ostendorp.
The fire went into storm drains and into the back yards of some of the homes. The soundwall along the road was damaged and several homes have been evacuated as a precaution.
"If we didn't have that wall, it would have definitely been on our neighbor's - our friend's backyard. Thank God that wall was there," said Clifton resident Suvi Patel.
The vinyl siding of the house behind that wall appeared to be completely melted off the side.
"I literally thought the hairs on my leg were going to burn off," said neighbor Anup Patel.
Emergency crews will work overnight to mill and pave the damaged portions of Route 3 eastbound, repair guardrail and install fencing and construction barrier where the soundwall was knocked down.
Police say drivers should avoid the area.
Officials with the Passaic Valley Water Commission said they are aware some customers in that area are experiencing discolored water.
----------
* Get Eyewitness News Delivered
* More New Jersey news
* Send us a news tip
* Download the abc7NY app for breaking news alerts
* Follow us on YouTube