Apple has told its European resellers and distributors that it intends to halt sales of the Mac Pro in EU countries on March 1, 2013. The reason cited is new regulatory requirements contained within Amendment 1 of the IEC 60950-1 Second Edition, which covers safety requirements for electrical, fire, heat, radiation, mechanical, and other hazards that may be present in equipment sold in EU countries.
Courtesy of Coyote Moon, Inc.
The Mac Pro meets all of the safety requirements currently enforced, but the new version of the regulatory documents has enough changes that Apple would need to add different finger guards for the internal fans, as well as a method to prevent exposure to electrical voltages on the PCIe bus used on the Mac Pro.
The changes needed aren't that difficult, but Apple has already said that it intends to release a new Mac Pro model sometime this year. It doesn't make sense to spend engineering and production time to retrofit changes into the current Mac Pro.