While in most cases green and grey indicate a Low Hazard or Risk situation. We understand some organizations such as USLA prefer grey, we decided against grey for the following reasons, Logical Arguments: Green as a indication color is universally understood while grey is not. Regardless of it’s implicit meaning out of context, education must compliment any safety policy, whether green or grey, and this is no different. The focus should be on uniformity and education less the color. Green flag systems are already implemented and well established around the country. Changing color code more broadly is a considerable undertaking and until obvious benefits are shown it’s unlikely to change. Beaches that prefer grey over green never use either to begin with. We’re limited on the number of colors in which are clearly differentiable from one another. Especially in high glare situations. Grey is not feasible so white is the only option. However, white is reserved for generic lighting which is used to illuminate our signs, callboxes, or area lighting for dawn/dusk emergency use.  Technical Realities: A reality of a lighted warning system is that grey will really have to be white. White light will appear as any other illumination such as headlights, streetlights, etc. In high glare situations it becomes very difficult for white light to overcome glaring cloud conditions. White light will quickly fade into the background after a few hundred feet. This is already somewhat true for our yellow lights. There is no sense in exasperating this issue. White light is technically a combination of various colors, in the context of LEDs a lot of white lights produce the color through combined colors which typically makes them more inefficient for the same given output power.  Based upon the light efficiency function (LEF) of the human eye, green is the most efficient while blue and purple are the least. Many white LEDs use a combination of blue to produce white. However, at night time blue is actually the most efficient, this is why many white LEDs for illumination purposes utilize a manipulated blue light spectrum.  Marine life such as sea turtles are sensitive to light wavelengths less than 560nm. While green is applicable here, blue has substantially smaller wavelengths. Thus, many localities have restrictions on lighting; white utilizing blue manipulation requires excess output power compared to green for the same visibility to the LEF. Note that our lights operate dawn to dusk and turn off at night. Ironically enough, purple (for stinging marine life) is the lowest wavelength and will require substantial corrective measures to be useful in these environments. Again, further exasperating problems where there don’t need to be is unnecessary.        Economic Arguments: Adding additional colors adds system complexity and additional part numbers. These extra part numbers translates into lower averaged quantities, additional engineering and support costs, per light which results in higher costs to the beaches. White lighted units will be rare and exceptionally more expensive for an inferior performing light.