Among the injured were police officers, firefighters and other rescue workers who had initially responded to a smaller explosion caused when a truck hit a gas pipe.

The second, much larger blast occurred in the northeast of Rome and was heard throughout the Italian capital, spreading fear among many Romans who initially thought a bomb had gone off. A thick plume of smoke was visible from all parts of the city.

The 45 injured individuals were treated in nine hospitals across Rome. Among them were local residents who were hurt by flying shards from shattered windows.

Medical sources said six people are in critical condition, with two of them on life support. The pair have burns covering 55 per cent and 25 per cent of their bodies, respectively, as well as inhalation injuries and barotrauma caused by the massive air displacement from the explosion.

Of the 45 injured, 24 are civilians, 12 are police officers, six are firefighters and three are emergency service personnel.

The manager of a nearby summer camp said it was fortunate the explosion happened early in the day, as it “would have been a massacre” if the usual 60 children and 120 swimming pool visitors had been present at the facility.

Fabio Balzani, the camp manager, said the early-morning visitors and the first children to arrive were promptly evacuated when the smell of gas was detected.

“At the first hints of smoke around 7:30 a.m., we evacuated the children; there were eight of them,” he said. “Their parents have arrived and all the kids are fine.

“If it had happened an hour later, it would have been a massacre. There would have been 60 children from the summer camp, staff and 120 people booked at the swimming pool. The sports centre is damaged; it looks like a battlefield.”

Italian Prime Minister Giorgia Meloni said she was in close contact with Rome Mayor Roberto Gualtieri to monitor the situation following the accident.

Pope Leo XIV said he was praying for the victims.

Rome prosecutors have opened an investigation into the incident.

In total, about 50 people were evacuated after the larger blast.

Environmental group Legambiente called for fewer petrol and gas stations in urban areas to improve safety, especially during the extreme heat of summer.

Taxpayer group Federcontribuenti criticised the location of the facility, saying it “should not have been placed in that location”.

Rome has 862 petrol and gas stations, of which 109 distribute liquefied petroleum gas (LPG), according to the Business and Made in Italy Ministry website.

Ennio Aquilino, Lazio Regional Firefighters’ Chief, said the explosion was caused by a malfunction in the gas plant.

“After our first intervention for a gas leak, which prompted firefighters to rush to the site, the big blast occurred. It was like a bomb going off,” he said.

Carabiniere Gregorio Assanti, who rescued the petrol station safety officer from a burning car, described the chaos:

“We were thrown back twice during the two large explosions,” he said, “The first time, when I got up, flames were blocking our view. But I managed to spot a man lying next to his car, which was on fire after the explosion. He was on the ground with burns all over his body, engulfed in flames.

“He was still conscious but in shock. We immediately helped him and tried to get him to the hospital, but the ambulance was on fire. We didn’t lose heart; we loaded him into one of our patrol cars, brought a nurse with us and drove him to the hospital. Then we went back to help others.”

Health authorities warned locals about the dangers of exposure to liquefied petroleum gas (LPG).

“LPG, a mixture of propane and butane, if inhaled in high concentrations, can cause nausea, dizziness, neurological disorders, loss of consciousness and, in the most severe cases, asphyxiation,” said the Italian Society of Environmental Medicine (SIMA).

“Direct contact with the cryogenic liquid can also cause cold burns and serious skin injuries,” SIMA added.

Residents were advised to keep their windows closed because of fumes and ash from the fire.

ANSA