[thachmai]

Metric ton sounds redundant to me. Does the US have the notion of a "imperial ton"? (1000lbs?)

[grzm]

Yes, tons do differ. A metric ton (or tonne) is 1000kg. In the US what’s commonly referred to as a ton is a short ton, or 2000 lbs.

[NeedMoreTea]

An imperial ton would be the British one, also known as a long ton. It's 2,240 lbs, which is slightly heavier than a metric tonne.