I recently worked on a project with three (3) processes built by three (3) different contractors from three (3) different countries. This business is located in the USA, and the other countries are South Korea, Japan, and China. As you can imagine, we (the USA) use the imperial units of measure, and these other countries do NOT. So we have adults who are struggling to make the switch to the South Korean, Japanese, and Chinese units of measure. And the differences are SIGNIFICANT. For example, the Japanese like to use Megapascal (MPa), and in the USA, we use Pounds Per Square Inch (PSI). 1 Mpa is equal to 145 psig. We do this with LEVEL and TEMPERATURE as well. So we have had to hold a training class just on the units of measure for these safety-critical parameters. We have to ensure that the SOPs and Checklists are written with BOTH imperial units and metric units. Just imagine an operator looking at a pressure gauge and anything over 10 psi is a problem, and yet the gauge reads 1.0 MPa!!! Trust me, what you just thought has already occurred. Throw in the fact that a small group of operators travels between the Japanese-built and South Korean-built processes. The South Koreans used Kilopascals (KPa) for pressure measurements. And 1KPa = 0.001 MPa or 0.145038 psi. Confused yet? Just imagine what an operator faces daily. And we all know that when an error occurs in these conversions (dozens happening every day), the root cause will be “operator error”. But is it really “operator error”? Of course not, this is a clear-cut case of a failure in Human Factors; more in line with a latent organizational failure. But this is why we cover Human Factors in our PHAs.