NEW YORK—The NHL announced Tuesday it would study the possible safety and injury risks of playing hockey on Astro-Ice, an artificial rink-surfacing material used by many teams instead of expensive and difficult-to-maintain ice, the solid state of water formed at low temperatures. "While we maintain there are many benefits to using Astro-Ice—increased slipperiness, ease of installation, no need for costly Zambonis—we realize the increased instance of players falling down indicates a need for further examination," a press release issued by the NHL read in part. "Until the study is complete, we urge all franchises using Astro-Ice to exercise utmost caution." Astro-Ice, a Dow Chemical product, includes many of the same components found in water-based ice, plus added binding polymers, artificial coloring, and additional hydrogen, which the NHL said was "almost certainly" not to blame for this year's dramatic increase in on-ice fires.