Aluminium was once thought to be a cause of Alzheimer's disease, but today's leading medical scientists believe there is no such connection. 97% of our daily intake of aluminium comes from food and additives and only 3% from aluminium foil, cans and kitchen equipment.

General fabrication of aluminium has no impact on human health, with the exception of welding for long periods of time, which can affect the lungs if insufficient air conditioning is present.

Scientifically, it has been agreed that aluminium is an inert substance, due to the formation of a stable oxide layer on contact with the air. However, hazardous situations can arise when the alloy is submitted to various processes such as anodising, painting, coating, welding, polishing, and thermal breaking.

Handling solids

Possibility of sharp edges, use gloves when handling. Aluminium experiences no colour change when heated - use gloves to protect against burns. Alloy must be completely free from moisture before charging into furnaces

Handling liquids

When melting, casting and processing, appropriate protective equipment must be worn, such as glasses, goggles or visor, metal-shredding overalls, foundry footwear and gloves. All tools used with molten metal must be dry.

Fire

Aluminium is not a fire hazard due to it's high thermal conductivity.

Explosion

Molten aluminium may explode upon contact with water, and many other substances including oxidation agents. All aluminium solids must be free from moisture before they are added to molten metal. Finely divided aluminium may explode when mixed with halogen acids (eg hydrochloric), halogenated solvents or ammonium nitrate.

Health & Toxicity

Aluminium has been found to be poorly absorbed by the body and little of the element entering the body through normal action remains. Aluminium has never been found to be toxic except under quite unusual conditions of exposure. At present,there is no direct clinical or experimental evidence that aluminium is neurotoxic under ordinary conditions of environmental exposure. The HSE recommended long term exposure limit (eight hour time weighted average) for aluminium metal and oxide in the air is 10 mg/m3 - the same as for all other nuisance dust. However, inhalation of any dust or fumes should be avoided. It is understood that aluminium metal and oxide, along with many other substances, will be reviewed by ACTS/WATCH. Until reviewed, exposure should be kept as low as reasonably practicable and the above limit should be used as guidance for the control of exposure.

At high temperatures, alloying elements and impurities such as magnesium, zinc and lead will volatise and give rise to fumes. Where fuming occurs, local extraction may be necessary to ensure compliance with the required exposure limits.

Storage

Keep dry, away from incompatible materials, including nitrates, acids and alkalis, which may result in fire and explosion.

Spillage

Solid aluminium presents no problem. Spillages of molten aluminium freeze up very quickly but substantial amounts may be dammed using DRY sand and DRY alumina.

Disposal

Recycle. Fine particles of aluminium may be reactive and its hazard characteristics should be determined prior to disposal.

Transport

Solid and liquid aluminium are not classified as dangerous for conveyance by road in the UK.

Anodising

Natural or silver anodising consists of a layer of hydrated aluminium oxide containing a little aluminium sulphate that is firmly bonded to the aluminium. This layer is between .005 mm and .025 mm and so represents a very small proportion of the section. It cannot become detached from the aluminium in normal operations but severe deformation can result in extremely small flakes being detached and possibly projected. It is therefore prudent to wear safety glasses when bending or punching. The coating Is non-toxic and very minute particles ingested will be dealt with by the body. When sawing there is a potential for dust, which like any other should be carried away from the operator by the extractor.

Coloured coatings may contain organic or inorganic pigments and oxides of tin, cobalt or magnesium. If strong acids and alkalis attack the film these substances may be released. Any sawing may release these in the dust, which should be carried away by an extractor as above. (See section on ANODISING )

Electrophoretic Paint

The white paint consists largely of titanium dioxide and a modified acrylic resin carried in solvents that are driven off during curing. Thus the cured coating itself presents no hazard in normal use. If the material is sawn then some paint particles may be released in the dust which though considered harmless in themselves may change by being inhaled through a lighted cigarette etc or if burned. The dust like any dust is considered hazardous and should be controlled by extraction. (See section on PAINTING )

Polyester Powder Coatings

Adequately cured and adherent coatings of polyester may be expected to present negligible hazard under normal conditions of use, where risk of transfer into the body is minimal. Some coloured coatings contain pigments of lead compounds which, although they are of low solubility, should not be used where they are likely to be sucked or chewed by children. Dust from sawing, etc, presents the normal hazard of any dust and should be controlled by extraction. Dust from coloured powder should be collected by vacuum and disposed of by approved means. Burning of the coating can produce harmful materials which will vary and depend upon the factors present during combustion but, could include Acrolein and other aldehydes, phthalic anhydride, phenol, nitrogen oxides, amines, hydrogen cyanide and low molecular weight free isocyanate. (See section PAINTING )

Welding

MIG-welding or plasma arc cutting of aluminium alloys can generate ozone, nitric oxides and ultraviolet radiation. Ozone over-exposure may result in mucous membrane irritation. Fumes may also arise from volatilisation of the electrode or its coatings. The inhalation of freshly formed metallic oxides such as cadmium, chrome, nickel that may be present as alloying constituents may cause welding fume fever. Good ventilation is recommended and observance of normal protective measures generally applicable to welding operators. It should be noted ozone can be generated quite a distance from the arc.

Polishing

The Regulations for the Grinding and Polishing of Metals must be observed. Extraction is essential. Extraction Ducts and, for that matter the whole area, inclusive of overhead beams and ledges, must be regularly cleaned. The use of water washed extraction is recommended. Ensure well ventilated to prevent accumulation of hydrogen. An aluminium particle plus polishing compound fire should be starved of air and cooled any attempt to clear the obstruction is hazardous. The provision of suitable clothing and toilet facilities is essential. The possibility of catching loose clothing, gloves, or even hands, in high speed rotating machinery is a major hazard. Suitable machine guards are required, and shaft safety sleeves used. There is a specific risk of dermatitis from polishing compounds. The golden rule is that a clean shop is the safest shop. (See section OTHER FINISHING METHODS )

Filling

This product involves the exothermic interaction of two chemicals to form a polyurethane polymer: the manufacture recommendations for handling the components must be followed. In addition, the presence of water, which modifies the reaction, must be avoided. Extraction of air from the process area is essential.

There are two mandatory rules during filling: - There must be no smoking in the department - it is suggested that the 'miners code' be adopted. This is not primarily a fire hazard: the chemical fumes will decompose if drawn through red-hot, burning tobacco giving highly toxic products.

Fire, most likely of electrical plant origin, is extremely dangerous: all precautions to prevent it must be taken. If there is a fire, however, there must be no attempt to extinguish it, immediate evacuation must be the rule. The local fire service must be informed of this potential hazard and may recommend the local provision of rescue, breathing equipment and the appropriate training in its use.

The storage of materials and the disposal of waste materials and 'empty' drums is controlled by the Control of Pollution Act. The use and particularly the welding or cutting of 'empty' drums must be prevented. An organic solvent (typically methylene chloride) often effects plant cleaning, the user of which must observe the supplier's recommendation.

After Curing & Milling

There is an almost identical material used to line and/or coat potable water and food containers. The two components used to create the thermal break, when dispensed in the correct ratio, are completely inert once they have reacted together and are fully cured. The material supplier regularly monitors the plant to ensure the ratios and dispensing are correct.

Sawing

Provided the material has been dispensed correctly as above, no hazardous fumes are given off when sawing through the material. The dust is a different proposition simply because it is a dust and any dust particle can be considered hazardous. The sawing equipment should be fitted with an exhaust facility to draw off and collect the dust particles. Any not collected should be regularly cleaned from the floor using a vacuum cleaner and dust from both should be carefully disposed of. The burning of the dust or inhalation through a lighted cigarette etc. can produce harmful products.