The Għarb factory should never have had so many fireworks in one place, especially when people were still working there, pyrotechnics inspector Servolo Delicata said yesterday.

"They went very much beyond the limit of what should have been stored on site," said Mr Delicata, who spoke to The Times just before his appointment on a board of inquiry set up to look into Sunday’s blast.

Mr Delicata said that although the law regulated the amount of potassium nitrate and chlorate (two of the most unstable fireworks materials) that can be kept in the factories, a newer compound, potassium perchlorate, was not regulated and, therefore, gave rise to a loophole.

"Small accidents happen in fireworks factories and it's very likely that a small explosion in the working area spread quickly because of the large amount of fireworks that were on site,"he said, explaining that a chain of explosions made it possible for the damage to be so wide-spread, so much so that the two men who were taken to hospital severely burnt,were standing 50 metres from the main blast site.

The explosion was so powerful it left a large crater in the ground. Debris could be found hundreds of metres away from the site of the factory. The ground was littered with petards and car parts could be seen a long distance away from what was left of the vehicles themselves.

Although many speculated that a fire could have started from trucks or the fireworks they carried, Mr Delicata thinks the trucks were not a likely cause. If something were faulty in the vehicles it would have most likely caused problems during transport not when they were parked, he argued.

The fireworks were carried to Gozo on a barge and taken by trucks to the factory, where they were parked in the yard. They were purchased from five factories in Malta: Għaxaq, Lija, Kirkop, Qrendi and the St Sebastian factory in Qormi, sources said. The Qormi factory claimed two lives last February when an explosion rocked the facility in the limits of Ħandaq, Qormi. An explosion occurred at the Għaxaq factory last year but luckily no one was injured.

In previous years, people at the Għarb factory site told Mr Delicata the fireworks bought from Malta were stored in separate places like, say, a container in the field where the explosives were going to be let off from. It was possible that there was a mistake somewhere,Mr Delicata said, but the fundamental problem being bred in factories was that "no one is scared anymore".

Most of the people who frequented the factories were not knowledgeable enough, he added.

Mr Delicata said it was too early to say what caused the blast or other unexplained explosions in the past months, which some are attributing to an inferior batch of chemicals.

However, he raised questions about the igniters, used to light up the fireworks. Although igniters have been used for several years, very little is known about them and their chemical consistency changed when they were bought from different companies, making them very dangerous.

Mr Delicata said that although the Farrugia factory was not known to use igniters that much, in the wake of so many casualties in the past year, he still thought igniters might have been a contributing factor in this tragedy. "Sometimes igniters go off on their own," he said. "I think that instead of calling a moratorium on fireworks for two years, we should call a moratorium on igniters."