The unit where five emergency service personnel were injured on Saturday night. Credit:Simon Schluter One of the women was left with extensive burns to her face and upper body. The other woman, the senior sergeant and two firefighters also suffered injuries. All three police had surgery. Police Association secretary Greg Davies said the incident highlighted the dangers first responders put themselves in to protect the public. “The people who are very quick to criticise the police for everything and anything they do should have a look at their attitude because they’re very lucky people like this are out there protecting the community,” he said. “Nobody deserves to go to work and have this happen to them, when they’re only trying to help a member of the public.”

Police in Middle Park on Sunday. Credit:Simon Schluter Although the explosion was a rare occurrence, Mr Davies said first responder police officers, who tend to be young recruits, were too frequently assaulted on the job. “We get more police every year get assaulted while their at work,” he said. Tony Morrison, who witnessed the blast aftermath. Credit:Simon Schluter “It’s a dangerous business and they’ve got to make split second decisions about things.

“Sometimes it doesn’t all go to plan and unfortunately these really tragic circumstances can occur.” One of the female officers had been in the force less than a year, while the other had been serving for about two years. “They had a very experienced sergeant with them and it's just one of those things — you can’t predict what other people are going to do,” Mr Davies said. Police believe the blast was the result of an LPG gas canister exploding, but have yet to determine how the flare-up occurred. The arson squad is investigating. Onlooker Tony Morrison, who was visiting his son-in-law with his wife, said he saw two people in ‘‘extreme pain’’ being sprayed with fire hoses.

‘‘The officers were just trying to comfort them, saying it would be okay," he said. ‘‘The female was in the most pain and was screaming in agony, and there was a male lying beside her on the ground too.’’ The explosion occurred about 9.15pm on Saturday night after crews responded to calls of a man threatening self-harm in Hambelton Street, Middle Park. Deputy Commissioner Tim Cartwright said police received a call at 8.13pm from family members expressing concern about the welfare of a male relative, aged in his 40s. The sergeant and two constables were dispatched to the flat to check on the man, who did not respond to repeated knocks.

The sergeant then called the fire-brigade about 9pm to help him gain access to the apartment. Deputy Commissioner Cartwright said firefighters provided a ladder to access the second-storey flat, and the three police officers – including the two firefighters – entered the apartment through the veranda door. ‘‘Very soon after that, we heard the explosion,’’ he said. ‘‘It blew out the windows and did quite a bit of damage.’’ The Deputy Commissioner said ‘‘preliminary investigations indicate this was a suicide attempt, rather than a malicious act’’.

The man, who is also being treated at The Alfred hospital, is under police guard until officers find out what happened, Deputy Commissioner Cartwright said. ‘‘He has also suffered burns, but is no worse than any of the members – at worst, stable with burns.’’ Another neighbour, Marlon Law, whose house backs onto the flat, helped hose down the worst-affected female officer and said other neighbours, including one doctor, also grabbed garden hoses to relieve the injured officers’ pain. "It was horrendous," he said. Mr Law said the female officer was still conscious through the ordeal.

"She was screaming in pain," he said. Mr Law said the male occupant of the house was also "pretty burnt" and paramedics worked to relieve his burns before placing him in an ambulance. "He didn’t really say or do much. He wasn’t running away, was on the ground and people were attending to him, but were mainly helping the one female officer who got quite severely burnt." Mr Law said his window looked directly into the burning flat, and that seeing the blaze and so many people at the scene was "pretty concerning". The two firefighters who were also injured in the blast have been released from hospital, suffering from minor injuries.

Deputy Commissioner Cartwright said ‘‘this is a a tragedy that cuts deep’’. ‘‘I’ve got to say this is probably the worst nightmare we have. ‘‘Our members deal with people experiencing mental illness everyday – in fact, we deal with an incident like this probably every hour in Victoria, and we invariably get it right,’’ he said. Apartment resident Nichole Abruzzise, 34, was sweeping up glass and debris in the communal car park on Sunday evening. “I felt the explosion rock the building and heard glass shattering … my heart stopped beating when it happened,” she said.

She said she was relieved to hear police did not consider the explosion ‘‘malicious.’’ “I’m at ease knowing he wasn’t trying to blow up the building.” She said she did not know the male occupant of the apartment well. “I sometimes saw him sitting on his balcony and waved,” she said. “He seemed quiet and nice.”

Another resident of the apartment block, who did not wish to be named, said the man kept to himself. He said it was typically a quiet apartment block, “a nice place to live”. Police have urged anyone with information to contact Crime Stoppers on 1800 333 000 or visit crimestoppers.com.au. With Chris Hingston For information about the prevention of suicide, contact Lifeline on 13 11 14, the SANE Helpline on 1800 18 SANE (7263) or Beyond Blue on 1300 22 4636.