Used primarily in soldering of
circuit boards and other device components

Extremely harmful to the human body; damages both the central and peripheral nervous systems; can cause seizures, retardation, high blood pressure, damage to the kidneys and liver; adversely affects child development

Forms significant portions of electrical connectors and
battery contacts

Long term exposure can be carcinogenic, especially for the lungs. Extreme exposure can lead to a potentially fatal condition known as Acute Beryllium Disease

Used in some integrated circuits
and semiconductors

Arsenic is a notoriously potent poison; causes severe damage to the digestive tract

Can be found to a degree in
batteries and circuit boards

Attacks the central nervous and endocrine systems; harmful to mouth, teeth and gums; poses risk in the neurological development of unborn fetuses

Used in production of diodes
and batteries. Pure form used
in semiconductor production

Toxic to humans in ways similar to arsenic; fatal in large doses

Used in soldering, semiconductors and chip resistors

Potentially carcinogenic; Repeated exposure can damage the lungs, kidneys and liver