WATCH: Last of Amigo's demolished after CBD inferno
UPDATE 5PM: The last remaining wall on Amigo's Bar and Grill on Margaret St has been pulled down as investigations into the fire continue.
Excavators arrived at the scene about 2.20pm, pulling pieces of charred wood and iron from the fire pit to allow investigators access to the believed point of ignition.
By 4pm, the last wall had been torn down.
Queensland Fire and Emergency Services Acting Chief Superintendent Megan Stiffler said the demolition had gotten under way as early as possible with public safety in mind.
Fire crews monitored the air around the fire scene throughout the day due to concerns over possible asbestos in the building.
Act. Chief Supt. Stiffler said once the last wall had been demolished, Margaret St would be reopened to all traffic and pedestrians.
4PM: Quest Toowoomba will likely be closed for the next two weeks because of damage from the fire which razed Amigo's Bar and Grill.
Guests at the serviced apartments on Margaret St were evacuated without incident moments before the inferno engulfed the neighbouring restaurant about 11.30pm on Tuesday.
It is understood several of the guests were in Toowoomba for the Darling Downs Tourism launch at Wellcamp airport that night.
A Quest spokeswoman told The Chronicle all 88 guests had been safely evacuated soon after smoke was seen coming from the Amigo's building.
"The 88 guests were all fine with no smoke inhalation," the spokeswoman said.
"Guests were redeployed to five other accommodation providers in the CBD.
"The damage was widespread but it was mostly external damage on the park (eastern) side."
The Quest spokeswoman said soft furnishings such as curtains and bedding was damaged on the eastern side, and the exterior would require some repairs.
The damage was mostly cosmetic, she said, and confirmed Quest would close for about two weeks.
"At the moment, people are being contacted who have bookings and we're in the midst of redeploying the people and are asking for patience," she said.
"(Staff) are going through inventories and are contacting all guests with bookings."
The hotel has 74 serviced apartments and the redeveloped site, built on the heritage-listed Church of Christ building on Margaret St, was opened in 2015.
NOON: Guests have been seen re-entering Quest Toowoomba on Margaret St as the full extent of the Amigo's Bar and Grill fire is revealed.
The multi-storey apartment block has been impacted by the blaze which razed the restaurant and Adrenalin rock climbing business last night.
The two businesses are charred wrecks with the sites reduced to rubble.
Quest balconies on the eastern side of the complex which looked over Amigo's, appear damaged in the fire with water running from those at the Margaret St side of the building.
Firefighters are continuing atmospheric testing in the building but it's understood the complex remains evacuated.
QFES Inspector Peter Bradow said guests had been able to re-enter the premises to gather belongings, assisted by police and firefighters.
The building, however, remains evacuated to all guests.
8.30AM: The inferno which razed Amigos and threatened the heritage listed church building at Quest Apartments could have been worse had it not been for the overwhelming response of firefighters.
At the height of the blaze, 52 firefighters from 12 appliances were at the scene, battling to ensure the flames didn't spread to neighbouring buildings.
Crews were brought in from neighbouring regions to contain the fire which QFES Chief Superintendent Megan Stiffler said started in the restaurant kitchen.
"We initially turned out two appliances and when they first arrived, there was smoke in evidence but no flames," Chief Supt. Stiffler said.
"When they entered, they saw the kitchen was well-involved, did a quick knock down and the fire from there escalated quickly.
"When they realised the extent of the fire they decided the exposures were the critical thing - they knew they weren't going to save the restaurant."
QFES resources from Oakey, Warwick and Highfields were drawn on, with an additional crew from the south-eastern region brought in to assist in containing the fire.
An aerial attack was also launched to fight the fire from above the roofline.
"I think it could have been a lot worse," Chief Supt. Stiffler said.
"Our crews did an amazing job considering how close the exposures were.
"The heritage listed church is (barely) metres away from where that fire was and on the other side, we had Toowoomba First Realty and the three-storey building.
"Both of those have come out with minimal damage.
"To keep the fire contained to the restaurant and the business at the back is a credit to the crews."
The morning has revealed the extent of the fire's wrath on the building with just a shell left standing on the Margaret St frontage.
The eastbound lane of Margaret St will remain closed for most of today into tomorrow as investigations continue into the cause.
"The initial crew found it well-involved in the kitchen area so that's where our fire investigators will start investigating today," Chief Supt. Stiffler said.
"They'll work with Queensland Police until that is identified.
"For us to call in resources from around the footprint like we did, it shows the severity of the fire and us realising that unless we put a weighted attack on it, it could have gone up the block.
"The tragedy is the business, they've built it up over 10 years and they have staff so while we're saying aren't we lucky, there's a lot of sad people worried about their employment as part of their loss."
7.30AM: Parts of Margaret St outside Amigos will remain closed until tomorrow as investigations continue into a major structure fire last night.
Toowoomba police said both east and westbound lanes of the CBD street between Neil and Hume Sts would remain closed until later this morning as emergency services clear the area.
Police said the westbound lane will open later this morning but it is anticipated the eastbound lane will remain closed through to tomorrow.
It is understood the area will be opened to foot traffic later today.
Church St behind the razed Amigos will reopen to traffic later this morning, but pedestrians are urged to avoid the area.
Police said the building was at risk of collapsing and posed a safety risk to the public.
EARLIER: A section of the Toowoomba CBD is off-limits today after a major fire ripped through the Amigo's Bar and Grill in Margaret St.
Police have blocked off access to Margaret St from Neil St to Hume St due to safety concerns and while investigations take place.
"Due to the extent of the blaze, a Public Safety Preservation Act declaration was made for the area bounded by Margaret St, Neil St, Chalk Lne and Hume St," a spokesman for the Queensland Police Service said.
Traffic is still flowing on Hume St.