January 21, 2016 1:06 PM EST

A judge in the United Kingdom confirmed Thursday that former Russian agent Alexander Litvinenko, who died in London in 2006, was killed by a fatal dose of polonium-210.

The finding once again brings radioactive substance polonium-210 to the headlines. A slew of of evidence makes the ruling not much of a surprise, but the substance itself is little known to the average person given that has few implications for most people’s everyday lives.

Polonium-210 is found in the natural environment, and is used in in the oil industry and to produce nuclear weapons. But in all of these cases it’s found at low concentrations. The Russian spies that experts suspect are behind the poisoning of Litvinenko likely used government resources, including a nuclear reactor, to make the chemical that killed him.

The dosage required to kill a person could easily be transported in a glass vial or another small container, according to the Royal Society of Chemistry. A quantity of the substance the size of a speck of dust would be enough to kill a person. The radioactive chemical travels throughout the body once ingested— in Litvineko’s case, it was put into his tea— and takes electrons from molecules in its path. Eventually, a person poisoned with the substance will die as the process of cell replication is diminished.

Judge Robert Owen said Wednesday that the order to kill Litvinenko may have been approved by Russian President Vladimir Putin. Russia has denied the charge.

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Write to Justin Worland at justin.worland@time.com.

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