A gas explosion at the Maternity and Children’s Hospital in the Cuajimalpa borough of Mexico City has caused at least two confirmed deaths and dozens of injuries. Rescuers continued late Thursday to comb through the rubble for other victims at the medical facility, which was largely destroyed.

The blast occurred when a tanker truck was supplying cooking gas to the hospital’s kitchen, when apparently a hose broke creating a massive leak.

The mayor of Mexico City, Miguel Angel Mancera, said at a news conference that at least two people, a woman and a child, had died and that more than 60 people were injured.

Officials had said earlier that seven people had died, but this number was revised to two, although 22 of the injured are in serious condition. At least 70 percent of the hospital was destroyed, and while none of the children registered in the hospital are confirmed missing, officials say there is the possibility that new patients who were visiting the hospital that day may be trapped under the rubble.

The explosion occurred at 7:05 a.m. when the fuel tanker was making a routine delivery of gas to the hospital kitchen. Witnesses said gas started to leak from a hose and workers tried for 15 to 20 minutes to stop the leak while gas started to accumulate.

Laura Diaz Pacheco, a laboratory technician, told the Associated Press, “The hose broke. The two gas workers tried to stop it, but they were very nervous. They yelled for people to get out. Everyone’s initial reaction was to go inside, away from the gas. Maybe as many as 10 of us were able to get out … The rest stayed inside.”

According to witnesses, people started to evacuate the hospital before a massive explosion caught on video caused a fireball and smoke that could be seen across the city. A much greater tragedy was avoided due to the fact that oxygen tanks within the hospital did not explode as well. Hospital staff reported there being nine babies in the hospital’s 35-bed nursery, one in serious condition before the explosion.

Injured mothers carrying their infants were reported fleeing from the wreckage as rescue workers searched through concrete and debris for any wounded and dead. The hospital was located in a lower-middle-class neighborhood of Mexico City and served poor and working class families with children. The hospital was built in 1993 and was part of the government health care system.

For now, authorities are attempting to scapegoat the gas truck driver and two employees who are hospitalized with serious burns while officially under arrest in connection with the explosion. The gas that was being delivered is a mixture of mostly propane or butane, known as liquefied petroleum gas, which is commonly used in Mexico for heating and cooking purposes.

The gas truck belonged to Gas Express Nieto, one of the four biggest gas providers in Mexico. Due to a lack of underground fuel systems in Mexico, most gas is transported via trucks, which has led to many deadly accidents like the explosion on Thursday. In February 2013, for example, 37 people died after an explosion rocked the headquarters of Pemex, the state energy company, in Mexico City after a gas build-up in the building’s basement.

In May 2013, a gas truck sped out of control on a highway in Mexico City and crashed into a poor neighborhood, killing 27 people, including 17 from one family. Last July, an accident also involving a hose from a Nieto gas truck killed three people in the city of Queretaro.

The lack of sound infrastructure and the ongoing efforts to privatize Mexico’s state energy company, Pemex, mean that such horrific accidents will continue to be a regular occurrence.