There were no fatalities, but a fireman wassuffered burneds during the fire.

It took 8 hours forto get the fire to be fullyunder controlled, t. The civil defense will have to demolish the entire factory building, as it was completely destroyeddamaged beyond repair.

'Get the fire under control' is more idiomatic. I'm not quite sure what you mean by civil defence however.

These types of fires often happen more due to the lack of inspection by the city hall and security agencies.

The factory was not workoperating at the time, for sure if there were employees working, ithere would certainly have been many fatal victims.ities

You could also say 'the factory was not in operation' or 'the factory was not running'

The factory owner iwas traveling abroad at the time of the incident.

I think this is meant to be past tense

He will certainly have to pay for the damage caused to the neighboring houses, in addition to the damage he had with the destructionloss of his factory.

'certainly' isn't wrong here, but it doesn't sound quite natural here

I hope he has insurance against fire and accidents. insurance.

At dawn yesterday a candle factory caught fire in a city 40 kilometers away from here.

what you have is not necessarily incorrect, but it is slightly awkward

There were no fatalities, a. A fireman was burned during the fire.

comma vs period, different clauses. This is known as a comma splice. It's common for even fluent speakers.

He slipped and melted plastic got inside his safety suit, which causedgave him second-degree burns.

Firefighters in the small city needed the help of the fire brigades in neighboring cities.

cities is plural. Brigades should be too.

It took 8 hours for the fire to be fully controlled, the civil defense corps will have to demolish the entire factory building, as it was completely destroyed.

Not positive about this. Usually you have a noun that the words civil defense would describe ie corps, guard, organization...

These types of fires often happen more due to the lack of inspection by the city hall and security agencies.

more is used for comparison.

You could write

These types of fires happen more than they should due to the lack of inspection by the city hall and security agencies.

The factory was not workoperating at the time, for sure. Certainly/clearly/evidently, if there were employees working, ithere would certainly havehave been many fatal victims.

He will certainly have to pay for the damage caused to the neighboring houses in addition to the damage he hasuffered with the destruction of his factory.