210Lead is used in some candles to treat the wick to ensure a longer, more even burn. Because of the
dangers, European and North American manufacturers use more expensive alternatives such as
zinc.
Lead glass is composed of 12–28% lead oxide. It changes the optical characteristics of the glass
and reduces the transmission of radiation.
Some artists using oil-based paints continue to use lead carbonate white, citing its properties in
comparison with the alternatives. Tetra-ethyl lead is used as an anti-knock additive for aviation fuel
in piston-driven aircraft. Lead-based semiconductors, such as lead telluride, lead selenide and lead
antimonide are finding applications in photovoltaic (solar energy) cells and infrared detectors.
Former Applications
Lead pigments were used in lead paint for white as well as yellow, orange, and red. Most uses
have been discontinued due of the dangers of lead poisoning. Beginning April 22, 2010, US federal
law requires that contractors performing renovation, repair, and painting projects that disturb more
than six square feet of paint in homes, child care facilities, and schools built before 1978 must be
certified and trained to follow specific work practices to prevent lead contamination.
Lead chromate is still in industrial use. Lead carbonate (white) is the traditional pigment for the
priming medium for oil painting, but it has been largely displaced by the zinc and titanium oxide
pigments. It was also quickly replaced in water-based painting mediums. Lead carbonate white was
used by the Japanese geisha and in the West for face-whitening make-up, which was detrimental
to health. Lead is the hot metal that was used in hot metal typesetting. It was used for plumbing
(hence the name) as well as a preservative for food and drink in Ancient Rome.
Until the early 1970s, lead was used for joining cast iron water pipes and used as a material for
small diameter water pipes.
Tetraethyllead was used in leaded fuels to reduce engine knocking, but this practice has been
phased out across many countries of the world in efforts to reduce toxic pollution that affected
humans and the environment.
Lead was used to make bullets for slings. Lead was used for shotgun pellets in the US until about
1992 when it was outlawed (for waterfowl hunting only) and replaced by non-toxic shot, primarily
steel pellets. In the Netherlands, the use of lead shot for hunting and sport shooting was banned in
1993, which caused a large drop in lead emission, from 230 tons in 1990 to 47.5 tons in 1995, two
years after the ban.
Lead was a component of the paint used on children's toys – now restricted in the United States
and across Europe (ROHS Directive). Lead was used in car body filler, which was used in many
custom cars in the 1940s–60s. Hence the term Leadsled.
Lead is a superconductor with a transition temperature of 7.2 K, and therefore IBM tried to make a
Josephson effect computer out of a lead alloy.
Lead was also used in pesticides before the 1950s, when fruit orchards were treated especially
against the codling moth. A lead cylinder attached to a long line was used by sailors for the vital
navigational task of determining water depth by heaving the lead at regular intervals. A soft tallow
insert at its base allowed the nature of the sea bed to be determined, further aiding position finding.