It is based on a non-hygroscopic (not absorbing air) dilithium nitrogen-rich salt that served as an oxidizer and red colorant.
To achieve the red-light emission from the flare, the authors report a formulation mixture of powdered magnesium and hexamine as fuels, nitrocellulose, an epoxy binder system, and lithium-based nitrogen salts as the oxidizer and color agent.
[1] Previously, many formulations for red-light-emitting pyrotechnics depended on a chemical reaction involving strontium chloride (SrCl).
[3] In 2014, the EPA made a decision to develop regulations on the amount of strontium present in drinking water.
The U.S. military training grounds were not included in the above study; therefore, the presence or percentage of strontium in their water systems were unknown.