Security guards kept ambulances from entering a Mexican resort following a deadly explosion last November, preventing emergency workers from rendering aid in the crucial first minutes after the blast, CBC News has learned.

The powerful explosion on Nov. 14 ripped through a small lobby of the Grand Riviera Princess hotel in Playa del Carmen, killing two Mexican workers and five Canadian tourists. Officials initially blamed swamp gas, but later determined a leaking gas line was to blame.

After cancelling a scheduled interview and following repeated interview requests, hotel officials sent an email to CBC News late Monday denying they had barred the ambulances from entering and saying it took ambulances 18 minutes to reach the facility.

Four people may face criminal charges in the homicide investigation, state officials say.

Emergency call timeline Eight emergency calls were placed following the explosion. Here's a basic timeline: 9:24 a.m.:First call made to 066, Mexico's equivalent of 911. The caller reports a fire in the kitchen. The operator asks whether there was an explosion. 9:26 a.m.:Second call made. 9:35 a.m.: Third caller reports an explosion in the lobby and asks that three ambulances be sent. 9:36 a.m.:Caller says a gas tank exploded and several people were hurt. 9:38 a.m.:Caller asks for help for a gas tank explosion in a kitchen. 9:41 a.m.:A police officer calls, saying a security guard won't allow ambulances on to the resort property and that the security guard did not have news of an event. 9:42 a.m.:Another caller requests ambulances. The operator explains that the ambulances have arrived at the hotel gate and asks for help getting someone at the resort to authorize allowing them into the gate. 9:43 a.m.: A policeman calls the operator to say security guards did not allow him inside.

Eight emergency calls made following the blast reveal that hotel security barred ambulances and police from entering the expansive resort complex, stranding them outside the front gate located about a kilometre from the blast site. At the same time, hotel staff and guests struggled to treat the wounded with limited supplies and expertise.

No one knows the precise minute of the blast, but it is believed to have happened at about 9:10 a.m.

The first emergency call to 066 — the Mexican equivalent of 911 — came in at 9:24 a.m., reporting a kitchen fire. Five other calls requesting ambulances follow.

At 9:41 a.m., about 17 minutes after the initial call, a police officer says ambulances are not being allowed on site by the security guard, who is unaware of any "event."

Hotel's image over lives

"We were all stopped," said Francisco Alor, attorney general of Quintana Roo state. "It was a very unfortunate situation with a lot of negligence. I could even hear on the radio the instructions of someone else in the hotel saying, 'Stop everyone.'"

Alor said he later called in the army to compel staff to allow him on the property. Hotel staff also later chased journalists, beating them with sticks and fire extinguishers.

"It is my perception, without any question, that the hotel tried to take care more of its image than solving the serious problem it was facing," Alor said.

Jose Efrain Chuc Chan, a Red Cross paramedic on scene that day, says he's encountered similar resistance at other resorts.

"When we go to pick up a patient of any kind of situation, right at the entrance we're told to turn off the siren and quietly enter the premises," Chan said. "It's complicated. Because we're trying to save their image, lives can be lost."

About 9:45 a.m., 21 minutes after the first emergency call, ambulances finally made it past the guards.

Lack equipment, training

At the opposite end of the resort, frantic hotel workers were trying to help those dying as well as 17 injured people with the hotel's limited supplies.

Hotel guest and British firefighter Jeff Westwell tried to help one of the Canadians killed in the blast: Malcolm Johnson, 33, of Nanaimo, B.C. Other Canadians killed were Elgin Barron of Ontario; Chris Charmont, 41, and his son John Charmont, 9, of Drumheller; and Darlene Ferguson, 51, of Ardrossan, Alta.

Malcolm Johnson was married on Nov. 10, 2010, days before the explosion that killed him. ((Canadian Press))

Though the veteran firefighter had 18 years of experience and certification for treating trauma victims, he said the hotel itself was ill-equipped and staff appeared poorly trained to deal with an emergency.

Westwell discovered Malcolm Johnson lying on the ground 10 metres from the lobby entrance, with three hotel workers standing over him.

An "extremely distressed" lifeguard ran up with a first aid kit, but the kit didn't have several items he needed, Westwell said, adding that hotel staff also appeared with oxygen cylinders but no regulators.

"They opened a cylinder and there was a loud blast of oxygen escaping," Westwell recalled in a written statement. "[A] Canadian woman tried to calm the staff down. They were panicking and in my view did not know how to use the rescue equipment."

Terra Charmont, who lost her husband and son in the blast, also recalled frantically yelling for medical supplies, including a defibrillator, but a worker told her the hotel had nothing.

"Nobody seemed to know anything," Charmont said. "A lifeguard wound up showing up with a box of Band-Aids and there were people lying on the ground looking like they had severe spinal issues."

Charmont spent hours trying to find out information about her husband and son, running back and forth between the destroyed lobby and the emergency desk set up about 800 metres away in the main lobby on the far end of the resort complex. The desk had little information and was often left abandoned, Charmont said.

By the time staff finally informed Charmont and her daughter, Megan, 10, that her husband and son had died, it was late afternoon. To her surprise, they tried to inject her with drugs to calm her down, she said.

Francisco Alor, state attorney general for Quintana Roo, says there was a "total lack of sense" the way the hotel communicated with the families of the deceased.

"I could feel a cold swab on my arm, and instantly I knew and I went, 'Oh my God, they're going to drug me. I didn't know with what,'" said Charmont, who batted the needle away.

"I looked up. Megan's screaming, 'Don't hurt my Mommy!' Here's a kid that's just had her world destroyed and the only support she has in the world is being held down in a chair with a hypodermic needle positioned above her."

The hotel did "everything possible" to handle the "devastating incident," Mascia Nadin, hotel director general, said in an email.

"No resort in the world can be fully prepared to handle a tragic situation of this size," Nadin said.

"Nevertheless, all that we could do during those frantic moments, apart [from] calling for rescue and emergency units, was trying to assist the wounded guests, calming those who witnessed the accident and try to limit the access to the affected area of the numerous extraneous people (i.e: local press and photographers) who just wanted to take advantage of the situation."

Worker's cheque never deposited

Sergio Villegas was one of two Mexican workers at the Grand Riviera Princess hotel killed in the blast. ((Courtesy of family)) Questions have also been raised about how the hotel treated the family of one of the two Mexican workers killed in the blast, Sergio Villegas.

Villegas's mother said she was shocked to discover the hotel never deposited Villegas's last cheque for the two weeks prior to the blast, worth more than $200 Cdn.

"The hotel has not taken any responsibility," said Martha Elena Marquez.

The family is struggling to care for Villegas's widow, four-year-old daughter, Aislyn, and four-month old son, Sergio.

Marquez says a hotel manager contacted the family and offered to pay basic funeral costs, but has so far offered no compensation or apology, Marquez said.

However, the hotel says it has supported the families of the two deceased workers and three wounded workers, who continue to receive medical help at a Cancun hospital.

The state attorney general has said that the ruptured gas line was part of an unauthorized pipeline extension.

However, the hotel says the line was "not improperly placed" and "no expert can state 100% why there was a leakage from this line."

Last month, the resort was slapped with a $486,000 Cdn municipal fine. Local media reported the penalty was due to original blueprints not matching the completed complex.

Before the explosion, the Grand Riviera Princess hotel, was also fined more than $4,900 Cdn for overbuilding on protected land. The complaint stated the hotel had filled in wetlands to expand its site, affecting the mangrove wildlife.