Researchers are updating camouflage face makeup so that it both hides soldiers and shields their faces from the heat of bomb blasts. Firefighters also could benefit from the new heat-resistant makeup. Soldiers have used face paint for centuries for one kind of protection to help their skin blend in with the natural environment and shield them. The new material continues that tradition, but also provides protection from the searing heat of roadside bomb blasts and other explosions. The detonation of a roadside bomb or any other powerful explosive produces two dangerous blasts. First is a blast wave of high pressure that spreads out at supersonic speeds, and a thermal blast follows almost instantaneously. It is a wave of heat that exceeds 1,112 degrees Fahrenheit. The thermal blast lasts only two seconds, but it can devastating for the face, hands, and other exposed skin. In an effort to protect soldiers from this threat, the US government has been seeking a solution consisting of a material that soldiers could smear on their faces like suntan lotion, leaving a coating that although thinner than a sheet of paper, could protect against that intense heat. The new forumula developed protects in laboratory experiments beyond the 2-second heat-wave threat. The new camouflage makeup protects the face and hands for up to 15 seconds before its own temperature rises to the point where a first-degree burn, which is a mild burn, might occur. In some tests, the new face paint can protect for up to 60 seconds, which could be important in giving soldiers time to move away from blast-related fires and also for use by civilian firefighters. The makeup had to meet several key criteria: It had to reflect intense heat; have camouflage colors suitable for day and night use; be easy to apply and remove; be waterproof; and be non-irritating to the eyes, nose, and mouth. The trickiest part was that the researchers had to avoid the use of mineral oil, mineral spirits, fatty substances, and other traditional hydrocarbon makeup ingredients. Hydrocarbons can burn in contact with intense heat in the flame spectrum. The team turned to silicones, which are not as flammable because they absorb radiation at wavelengths outside of the intense heat spectrum. Silicones have been replacing hydrocarbons in many commercial cosmetic makeup products as cosmetics companies improve products to confer better feel properties and transfer-resistance. Another challenge was adding DEET, an insect repellent. The military mandates that all camouflage makeups contain 35 percent DEET, but DEET also is flammable. The researchers successfully included DEET by encapsulating it in a hydrogel substance, a water-rich material that prevented DEET from catching fire. It already has passed the preliminary laboratory tests needed to determine whether development should continue. The researchers also plans tests of the material on other surfaces to try to protect clothing, tents, and other items from burning, and a colorless version is being developed for firefighters.