Balconies in this Melbourne apartment building have been patched up with wood following multiple glass explosions. Credit:Joe Armao It is also a startling example of growing issue of poor quality building materials making their way into Australia on shipping containers, unchecked, before being installed in homes and on buildings – in some cases threatening lives and property. "It's a huge problem and more than we know about it," said the chief executive of the Australian Window Association, Tracey Gramlick. Ms Gramlick said the prevalence of building products that did not meet Australian standards, combined with poor workmanship and installation, meant many buildings would have to undergo repairs in years to come. The Housing Industry Association said the majority of building products entering the country were not being tested by customs officials to ensure they complied with Australian standards.

Other products, including materials laced with asbestos, are arriving with fraudulent compliance certificates. While spontaneous glass breakage is thought to be rare, Fairfax Media has been made aware of at least three buildings in Melbourne where a number of explosions have occurred. Construction law expert, Andrew Whitelaw, said a builder was recently forced to replace a number of glass balustrades on a residential tower in Melbourne's CBD due to the discovery of nickel sulfide impurities. "If there is too much nickel sulfide in the mix, then extreme changes in temperature can cause the glass to have a pressure point and fail," said Mr Whitelaw, a partner at TressCox Lawyers. There have also been two separate explosions in recent months at an inner-city apartment tower. Both incidents were caught on camera and show that if the glass had shattered just a few seconds later, pedestrians would have been walking directly underneath.

The company investigating the cause of the explosions, Roscon, believe the builder may have been given certificates by the manufacturer falsely claiming the glass underwent a heat soaking process to remove the nickel sulfide. The result of a suspected balcony explosion. Roscon's national general manager, Sahil Bhasin, said a heating process is meant to break any glass with nickel sulfide it in before it is sent out to the marketplace. "That's the preferred option – to bust in an oven in China – rather than to be put up on building facades," Mr Bhasin said. "But sometimes we are finding these processes are being cut out, maybe to save money."

Mr Bhasin said there were also three separate glass balcony explosions at a multi-storey apartment in Malvern late last year, and in that case the builder could not provide any documents showing compliance with Australian standards. He said when he approached glass manufacturers for testing data they often provided certificates that appeared to be falsified, because the date on the document was the date they asked for the data, months or years after the glass was actually manufactured. "They are just issuing certificates willy nilly," Mr Bhasin said. Missing glass following a balcony collapse in central Melbourne. There is evidence substandard building products are rife throughout the construction industry. A 2015 survey of 739 builders and trade contractors by the Housing Industry Association found more than 30 per cent had to replace building products used in their projects because they had failed.

Consumer Affairs Victoria received 771 complaints and enquiries about "major failures" of or defects in building goods in the last six months of 2016. The Housing Industry Association said fraudulent certification had been discovered with plumbing, electrical fittings, window, engineered wood and steel products. But building products were rarely tested by customs when entering the country, the association said. The Housing Industry Association's chief executive of industry policy, Kristin Brookfield, said she advised her members to check for spelling mistakes and "photocopies of photocopies" as signs compliance certificates may have been falsified. A new concern is the presence of asbestos in construction materials, including plasterboard, that has been declared "asbestos free" by manufacturers in China. The Department of Immigration and Border Protection said it did not have "a legislated role" to check imported building products conform to standards.

However Border Force has been proactively targeting the importation of asbestos and has made four discoveries of asbestos in building products. The continued rise in imported building products, some purchased online, has seen growing calls for a mandatory or voluntary certification scheme, where building products are tested before being declared safe for use in Australian buildings for certain uses. There are also demands for the existing regulations to be more rigorously policed, with Victorian Planning Minister Richard Wynne calling for more inspections to be conducted on building materials coming into Australia. "The federal government needs to play a more active role in preventing suspect materials from turning up on our construction sites," Mr Wynne said. Loading

Mr Whitelaw said builders would always seek to maximise their profits. "There certainly is an issue about the quality of product being used at the moment," he said. "I think you can't put a cost on life, health and safety."