if the colours are a problem then CHANGE THE COLOURS
That's a great solution, but a very long-term and expensive one. There are numerous standard colour codes used in all sorts of industries. Warning lights, navigation, electrical wiring, map colour codes. It would be great if they could be standardised to colours that are agnostic to an individual's perception of colour. Remember though that CVD is not a single entity. Some types are more common than others, but it is so much more than just red/green.
it was discovered that about 68% of the workers on the site were colour blind
That must have been a very odd population, or there was something causing acquired deficiencies in colour vision. Acquired deficiencies are pretty common in fact. Eye disease, some medications, even prolonged solar damage can cause changes in colour vision.