In 2016, citing health concerns, the American Medical Association (AMA) issued guidelines (CSAPH Report 2-A-16) advising, among other recommendations, to impose a limit on the spectral properties of outdoor and roadway lighting. As a result, Gresco has received numerous questions on correlated color temperature (CCT) and a possible move to 3000K or lower color temperature for outdoor lighting. We have been following the industry’s reaction to the AMA report and want to share the most up-to-date response from the lighting community.

The Illuminating Engineers Society (IES), in conjunction with the International Association of Lighting Designers (IALD), approached AMA on a collaborative review of the CSAPH 2-A-16 report and its findings. The technical committee cited concerns that only one component of light exposure was evaluated for its impact on sleep disruption, and light levels and duration of exposure were not factored into analysis. They concluded that a more comprehensive study would be required. The AMA process did not allow IES and IALD to have a direct dialog with their organization. With the uncertainty of further studies and findings, IES issued a statement this September.

The gist of the statement is that more studies are required to determine the point at which higher CCT poses a greater risk to human health. Per the Department of Energy, the majority of LED lighting sources in use are at 4000K for roadway and parking lots and 5000K for parking decks. We don’t believe we will see a significant change in the outdoor market based on the AMA report.

Read the full IES Board Position Statement on their website.

Want more lighting resources from IES?  Check out their upcoming webinars at

If you have any other questions about lighting or would like more information, call Gresco at 855-705-1800.