Active euthanasia entails the use of lethal substances or forces to kill and is the most controversial means.

They were acquitted of a more serious poisoning charge, mixing lethal substances in drinks.

Asbestos is the most lethal substance ever widely used in the workplace.

The stuff that furs up coronary arteries must be one of the most lethal substances known to man.

The amount must have been precisely calculated, for a person could survive only the very smallest dose of this lethal substance.

Plutonium is the most lethal substance known to man-a spoonful of it could wipe out a city.

The murder was committed by means of poison or a lethal substance.

A flash of paranoia: had some demented person injected a lethal substance into the milk?

But while the lawyers say they are zeroing in on another potentially lethal substance, their opponents counter that there is no medical crisis.

For example, people drank beer and not water, because water was so contaminated that it became "a lethal substance."