LEAD METAL (LEAD : THE VERSATILE METAL)

Over the centuries lead's unique properties have been harnessed in countless ways in the service of man and today it is still one of the most widely used and versatile materials in existence.

Its softness and low melting point make lead very easy to handle and fashion. Its high resistance to corrosion makes it ideal for weatherproofing buildings and for equipment used in the manufacture of acids. Lead's high density makes it particularly appropriate as a shield against radiation in the nuclear industry and in hospitals. For the same reason lead is also good at stopping sound waves and so is used to reduce noise from machinery in factories and from engine rooms on ships.

However, the most important use of lead today is in the lead-acid battery which provides power in numerous situations. The most familiar use of the lead-acid battery is to start our cars and other vehicles, but they are also used to power electric vehicles and to provide emergency power when the electricity fails.

The qualities of lead are unrivalled and it is irreplaceable in many of its uses. Consequently this versatile metal will be needed as much in the future as it has been in the past.

Global Lead Mine Production, Metal Production and Metal Consumption 1964-2003

Sources and Production

Lead metal is described as being either primary or secondary. Primary lead is produced directly from mined lead ore. Secondary lead is produced from scrap lead products which have been recycled.

Around 3 million tones of lead are mined in the world each year. Lead is found all over the world but the largest mining countries are Australia, China and the United States, which between them account for more than 50% of primary production.

The most common lead ore is galena or lead sulphide. Other elements frequently present include zinc and silver. In fact lead ores constitute the main sources of silver, contributing substantially towards the world's total output.

Lead is obtained from galena by a process called smelting. This involves roasting the ore to remove the sulphur and to obtain lead oxide which is then reacted with coke in a furnace. The resulting lead bullion contains many impurities such as silver and gold (hence the name bullion) as well as antimony, arsenic, copper, tin and zinc. These impurities are then removed by various refining steps to obtain pure lead.

End Uses of Lead

Lead Use by End Consumption 2001

Recycling

A further 3 million tones of lead are produced from secondary sources each year, by recycling scrap lead products such as sheet, pipe and batteries. In fact in the western world today more lead is produced by recycling than by mining.

At least three-quarters of all lead used goes into products which are suitable for recycling. This is why lead has the highest recycling rate of all the common non-ferrous metals.

The use of secondary metal makes some important contributions to the environment:

Firstly, the recovery of lead from scrap requires far less energy than smelting from ore.

Secondly, recycling keeps unwanted products out of the waste stream and puts them to good use.

Thirdly, recycling conserves our natural resources for the benefit of future generations.

Key World Statistics 2003 (values shown in tones)

Product Identification

Synonyms : Granular Lead, Pigment Metal; C.I. 77575
CAS No. : 7439-92-1
Molecular Weight : 207.19
Chemical Formula : Pb

Hazards Identification

Emergency Overview
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POISON! DANGER! MAY BE FATAL IF SWALLOWED OR INHALED. CAUSES IRRITATION TO SKIN, EYES AND RESPIRATORY TRACT. NEUROTOXIN. AFFECTS THE GUM TISSUE, CENTRAL NERVOUS SYSTEM, KIDNEYS, BLOOD AND REPRODUCTIVE SYSTEM. POSSIBLE CANCER HAZARD. MAY CAUSE CANCER BASED ON ANIMAL DATA. Risk of cancer depends on duration and level of exposure.

Potential Health Effects
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Inhalation :
Lead can be absorbed through the respiratory system. Local irritation of bronchia and lungs can occur and, in cases of acute exposure, symptoms such as metallic taste, chest and abdominal pain, and increased lead blood levels may follow. See also Ingestion.

Ingestion :
POISON! The symptoms of lead poisoning include abdominal pain and spasms, nausea, vomiting, headache. Acute poisoning can lead to muscle weakness, "lead line" on the gums, metallic taste, definite loss of appetite, insomnia, dizziness, high lead levels in blood and urine with shock, coma and death in extreme cases.

Skin Contact :
Lead and lead compounds may be absorbed through the skin on prolonged exposure; the symptoms of lead poisoning described for ingestion exposure may occur. Contact over short periods may cause local irritation, redness and pain.

Eye Contact :
Absorption can occur through eye tissues but the more common hazards are local irritation or abrasion.

Chronic Exposure :
Lead is a cumulative poison and exposure even to small amounts can raise the body's content to toxic levels. The symptoms of chronic exposure are like those of ingestion poisoning; restlessness, irritability, visual disturbances, hypertension and gray facial color may also be noted.

Aggravation of Pre-existing Conditions :
Persons with pre-existing kidney, nerve or circulatory disorders or with skin or eye problems may be more susceptible to the effects of this substance.

First Aid Measures

Inhalation :
Remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical attention.

Ingestion :
Induce vomiting immediately as directed by medical personnel. Never give anything by mouth to an unconscious person. Get medical attention.

Skin Contact :
Immediately flush skin with plenty of soap and water for at least 15 minutes. Remove contaminated clothing and shoes. Get medical attention. Wash clothing before reuse. Thoroughly clean shoes before reuse.

Eye Contact :
Immediately flush eyes with plenty of water for at least 15 minutes, lifting lower and upper eyelids occasionally. Get medical attention immediately.

Fire Fighting Measures

Fire :
Not considered to be a fire hazard. Powder/dust is flammable when heated or exposed to flame.

Explosion :
Not considered to be an explosion hazard.

Fire Extinguishing Media :
Use any means suitable for extinguishing surrounding fire. Do not allow water runoff to enter sewers or waterways.

Special Information :
In the event of a fire, wear full protective clothing and NIOSH-approved self-contained breathing apparatus with full facepiece operated in the pressure demand or other positive pressure mode. Can produce toxic lead fumes at elevated temperatures and also react with oxidizing materials.

Accidental Release Measures

Ventilate area of leak or spill. Wear appropriate personal protective equipment as specified in Section 8. Spills: Sweep up and containerize for reclamation or disposal. Vacuuming or wet sweeping may be used to avoid dust dispersal. US Regulations (CERCLA) require reporting spills and releases to soil, water and air in excess of reportable quantities. The toll free number for the US Coast Guard National Response Center is (800) 424-8802.

Handling and Storage

Keep in a tightly closed container, stored in a cool, dry, ventilated area. Protect against physical damage. Isolate from incompatible substances. Areas in which exposure to lead metal or lead compounds may occur should be identified by signs or appropriate means, and access to the area should be limited to authorized persons. Containers of this material may be hazardous when empty since they retain product residues (dust, solids); observe all warnings and precautions listed for the product.

Exposure Controls/Personal Protection

Airborne Exposure Limits :
For lead, metal and inorganic dusts and fumes, as Pb:- OSHA Permissible Exposure Limit (PEL): 0.05 mg/m3 (TWA)
For lead, elemental and inorganic compounds, as Pb:- ACGIH Threshold Limit Value (TLV): 0.05 mg/m3 (TWA), A3 animal carcinogen
ACGIH Biological Exposure Indices (BEI): 30 ug/100ml, notation B (see actual Indices for more information).
For lead, inorganic:- NIOSH Recommended Exposure Limit (REL): 0.1 mg/m3 (TWA)

Ventilation System :
A system of local and/or general exhaust is recommended to keep employee exposures below the Airborne Exposure Limits. Local exhaust ventilation is generally preferred because it can control the emissions of the contaminant at its source, preventing dispersion of it into the general work area. Please refer to the ACGIH document, Industrial Ventilation, A Manual of Recommended Practices, most recent edition, for details.

Personal Respirators (NIOSH Approved) :
If the exposure limit is exceeded and engineering controls are not feasible, a half-face high efficiency particulate respirator (NIOSH type N100 filter) may be worn for up to ten times the exposure limit or the maximum use concentration specified by the appropriate regulatory agency or respirator supplier, whichever is lowest. A full-face piece high efficiency particulate respirator (NIOSH type N100 filter) may be worn up to 50 times the exposure limit, or the maximum use concentration specified by the appropriate regulatory agency or respirator supplier, whichever is lowest. If oil particles (e.g. lubricants, cutting fluids, glycerine, etc.) are present, use a NIOSH type R or P filter. For emergencies or instances where the exposure levels are not known, use a full-facepiece positive-pressure, air-supplied respirator. WARNING: Air-purifying respirators do not protect workers in oxygen-deficient atmospheres.

Skin Protection :
Wear impervious protective clothing, including boots, gloves, lab coat, apron or coveralls, as appropriate, to prevent skin contact.

Eye Protection :
Use chemical safety goggles and/or full face shield where dusting or splashing of solutions is possible. Maintain eye wash fountain and quick-drench facilities in work area.

Other Control Measures :
Eating, drinking, and smoking should not be permitted in areas where solids or liquids containing lead compounds are handled, processed, or stored. See OSHA substance-specific standard for more information on personal protective equipment, engineering and work practice controls, medical surveillance, record keeping, and reporting requirements. (29 CFR 1910.1025).

Physical and Chemical Properties

Appearance : Small, white to blue-gray metallic shot or granules.
Odor : Odorless.
Solubility : Insoluble in water.
Density : 11.34
% Volatiles by volume @ 21C (70F) : 0
Boiling Point : 1740C (3164F)
Melting Point : 327.5C (622F)
Vapor Pressure (mm Hg) : 1.77 @ 1000C (1832F)

Stability and Reactivity

Stability : Stable under ordinary conditions of use and storage.
Hazardous Decomposition Products : Does not decompose but toxic lead or lead oxide fumes may form at elevated temperatures.
Hazardous Polymerization : Will not occur.
Incompatibilities : Ammonium nitrate, chlorine trifluoride, hydrogen peroxide, sodium azide, zirconium, disodium acetylide, sodium acetylide and oxidants.
Conditions to Avoid : Heat, flames, ignition sources and incompatibles.

Toxicological Information

Toxicological Data : Investigated as a tumorigen, mutagen, reproductive effector.
Reproductive Toxicity : Lead and other smelter emissions are human reproductive hazards. (Chemical Council on Environmental Quality; Chemical Hazards to Human Reproduction, 1981).
Carcinogenicity : EPA / IRIS classification: Group B2 - Probable human carcinogen, sufficient animal evidence.
-------------------\Cancer Lists\-----------------------------------------------------------------------
                                            ------NTP Carcinogen------
Ingredient                                            Known             Anticipated          IARC Category
------------------------------------------- ------------------ ------------------------ ----------------------
Lead (7439-92-1)                                   No                       No                          2B

Ecological Information

Environmental Fate : When released into the soil, this material is not expected to leach into groundwater. This material may bioaccumulate to some extent.
Environmental Toxicity : No information found.

Disposal Considerations

Whatever cannot be saved for recovery or recycling should be managed in an appropriate and approved waste facility. Although not a listed RCRA hazardous waste, this material may exhibit one or more characteristics of a hazardous waste and require appropriate analysis to determine specific disposal requirements. Processing, use or contamination of this product may change the waste management options. State and local disposal regulations may differ from federal disposal regulations. Dispose of container and unused contents in accordance with federal, state and local requirements.