Prosecution Details

Being an employer failed to ensure, so far as practicable, that the safety or health of a person, not being its employee, is not adversely affected wholly or in part as a result of any hazard that arises from or is increased by the work that has been or is being undertaken by the accused or any employee of the accused, or the system of work that has been or is being operated by the accused, and by that failure caused the death of, or serious harm to, a person; contrary to sections 21(2)(b) and 21A(2) of the Occupational Safety and Health Act 1984.

The accused was, at the time of the offence, the operator of a metal foundry at 19 Cockburn Road in Henderson. The accused bought the foundry operations from Roche Castings Pty Ltd by agreement of sale dated 19 January 2005 with occupational control being handed over on 1 April 2005.

On 6 April 2005 the accused employed approximately 180 people to work at the foundry, and also engaged some labour hire workers through an arrangement with Integrated Group Limited.

In the accused's operations at the foundry electric induction furnaces were used to heat constituent materials to form a specified metal alloy (a "melt"). This type of furnace is a large cylindrical vessel surrounded by copper coils which are filled with water. The copper coils induce a current in the constituent ingredients placed inside the furnace causing them to melt. The furnace is lined with a substance to protect the furnace from the melt. The lining is rated to withstand temperatures above those occurring in the normal melting process within the furnace. The procedure of adding the constituent materials is referred to as "charging" the furnace.

It is well known in the industry that one of the risks when using electric induction furnaces is that molten metal may pierce through the lining of the furnace and cause the surrounding copper coil to melt. This brings water into contact with molten metal. The temperature of the molten metal causes the water to convert to steam and expand rapidly which may result in an explosion of molten metal out of the furnace.

One well-known mechanism by which this can occur is by a phenomenon described as "bridging". This occurs when a hard cover or "bridge" forms over the top of molten metal in the furnace, which causes the molten metal below to superheat to such an extent that it prematurely erodes the furnace lining allowing the molten metal to come into contact with the copper coil and the water within. The risk of bridging can be minimised by charging the furnace correctly having regard to the size and melting point of the constituent materials. Once a bridge has occurred the correct procedure for dealing with the situation is to turn the furnace power off to prevent further heating of the trapped molten metal, and to attempt to put a hole in the bridge so as to allow cold material to be added to the molten metal below and to bring the molten metal up to the level of the bridge and thereby melt the bridge.

One of the alloys made by the accused at the Henderson foundry was a stainless steel alloy described as HA28. One of the constituents of HA28 was low carbon chrome. Low carbon chrome is a constituent that will easily bridge when being melted if not charged properly.

There was no specific procedure in place as to how to charge the HA28 melt. The method of adding the low carbon chrome was done a variety of ways at the Henderson foundry including by adding it all in one bulk lot. Adding the low carbon chrome all in one bulk lot increases the risk of a bridge occurring.

Some of the employees of the accused had attended training in relation to bridging by the manufacturer of the induction furnaces in 2003. However, not all of the relevant employees working at the Henderson foundry in April 2005 had been to the training course in 2003. No assessment of the competencies of the relevant employees with respect to bridging was carried out by the accused or by the previous owner of the foundry.

On 6 April 2005 an employee who usually acted as chargehand to an experienced furnaceman, was instructed to carry out the duties of a furnaceman for the day and to carry out an HA28 melt. The leading hand on duty that shift was responsible for supervising this employee. Neither employees had received adequate training concerning "bridging".

Following the accused's formula for making an HA28 melt, the leading hand worked out the weight of the relevant constituent ingredients for the melt and advised the furnaceman of these. When charging with the low carbon chrome the furnaceman loaded approximately 900kg at once into the furnace. Both employees had seen low carbon chrome added this way previously, as well as other ways and had not been given any instruction as to how the low carbon chrome was required to be added. The correct method of charging this amount of low carbon chrome would have been to add no more than approximately 200kg at a time ensuring the quantity added had successfully melted before adding more low carbon chrome in order to minimise the risk of bridging.

At about this time an employee of Integrated Group Limited who had been sent to the Henderson foundry that day to commence working there for the accused, had undergone his general induction to the workplace and had been taken onto the furnace deck to be shown that area of the workplace and to observe the operation of the furnace.

The furnaceman was standing over the furnace and prodding the low carbon chrome with a crow bar when he observed what appeared to him to be an electrical spark arc from the furnace to his foot. At that time the ground leak detector on the furnace was activated and the furnace tripped out. The leading hand noticed that the top of the furnace looked "frozen or compacted" at about that time. In fact at that point the material in the furnace had bridged so that there was a solid cover of un-melted metal over the surface of a pool of molten and melting metal.

The leading hand asked an electrician at the foundry, to attend to the furnace. After they had observed the power panel for the furnace the ground leakage alarm was reset and the furnace reactivated. None of the staff realised that the material in the furnace had bridged.

Shortly afterwards a mass of molten metal exploded out of the furnace. The employee of Integrated Group Limited was covered by the molten metal and caught fire. He died as a result of the injuries sustained in the explosion. The furnaceman suffered a left shoulder dislocation and superficial burns and another employee suffered temporary hearing loss and superficial burns as a result of the explosion.

Pleaded Guilty