Other communities talk about radiation risk in terms of radiotion you get from a banana.
It's about as useful as double-decker buses or football fields.
Short ton: 2000 lb.
Imperial (UK) long ton: 2,240 lb.
Longweight ton: 2400 lb.
I'm in the boat business where a register ton is 100 cubic feet.
There are more, especially once you get to other types of pounds.
Likewise, confusion between "mills" (millimetres) and "mils" (thousandths of an inch) are an exclusively American problem.
The American adherence to customary units is a constant annoyance for electronics engineers - an 0603 resistor could measure 0.6mm x 0.3mm or ~1.5mm x ~0.76mm
A resistor measuring ~0.6mm x 0.3mm is an 0201. (2 1/100ths of an inch by 1 1/100th of an inch.) The standard doesn't make sense in SI units, but it's the standard.
http://www.newark.com/chip-smd-resistors/resistor-case-style...
The metric/imperial split is a constant nuisance. Most board houses and PTH packages use mils, but the vast majority of SMT IC packages are specified in millimetres. Board layouts almost always necessitate switching between imperial and metric units; Layout software includes features to manage this. Wire gauges are a total mess - AWG, SWG and mm are all in common use. Standard pin headers and derivative connectors are 0.1" pitch (2.54mm), but JST connectors are 2.5mm pitch. Conversion errors have caused countless production problems.
EDIT: Correction, all except for the number for recovered steel.
[1] http://images.apple.com/environment/pdf/Apple_Environmental_...