The original source of this additive (or the raw materials for it) was a waste product from detergent manufacture. When that method of detergent production was

The original source of this additive (or the raw materials for it) was a waste product from detergent manufacture. When that method of detergent production was discontinued, they needed to set up an alternative source, which no doubt raised the cost, but everything about the A12 / SR71 was hugely expensive.