Four people were injured when a gas explosion ripped through a hotel in Thailand.

Employees at The Canal Ratchaburi Hotel in Ratchaburi province were in the kitchen preparing meals for staff when a fuel cylinder exploded, sending shockwaves that caused the building to partially collapse on the morning of June 20.

Firemen responded to the explosion after receiving a report at around 9:30 am. They found the building partially collapsed, with the windows blown out and several aircon units hanging from the two-storey building.

They pulled four injured workers out of the rubble. They were identified as cook Thongla Rachawong, 51, and hotel staff Praphas Praisuwan, 44, Amporn Khammonthao, 51, and Somboon Auam-im, 50. Thongla and Praphas were said to have serious injuries. All of them were rushed to the hospital.

Ratchaburi police officers inspected the hotel and found six 48kg gas cylinders undamaged. A destroyed 15kg fuel tank was found on the hotel's first storey.

Police Major General Wachirapong Amarapitak, commander of Ratchaburi Provincial Police, said: 'We believe the staff may have forgotten to properly close the fuel tank valve, leading to the explosion.

'We also found that the building was primarily constructed using lightweight concrete. The material may have contributed to the building's vulnerability and swift collapse. However, experts will conduct a thorough investigation later.'

The hotel manager said she was in her room about a kilometre away from the blast site, when she heard the blast. She ran to the hotel and found the four wounded employees shouting for help.

She said: 'Since the hotel was not open for serving customers on that day, the only people who were injured in the incident were the hotel staff present at the time.

'Before the explosion, the cook was in the kitchen with another staff worker, while the other two victims were outside the building.'

Police have cordoned off the area and were assessing the extent of the damage.

Authorities said a more thorough investigation will be done once the scene was deemed safe to investigate.

Deputy Ratchaburi Governor Udom Petchkut, along with relevant organisations, conducted an inspection of the area to investigate the cause of the explosion.

Additionally, he said compensation and assistance would go to injured workers.

Udom ordered the provincial office of Public Works and Town & Country Planning to collaborate with the provincial forensics police in determining the cause of the explosion and building collapse, as well as assessing the extent of the damage.

During the thorough inspection, if it is determined that the structural damage is significant, Udom Petchkut will issue an order for the building to be demolished.

During the interview, Wachirapong mentioned that a preliminary investigation indicated that the explosion was caused by a gas cylinder leak, resulting in damage to the building.