One of the first chemicals mentioned in the initial request was H₂S, or hydrogen sulfide. Enabling the new sensors to detect that specific chemical allowed for further development in recognizing other hazardous gases. “Now we have expanded it to six to seven gases,” Ambal Jayaraman, principal engineer and investigator at TDA Research told SIGNAL Media. Besides hydrogen sulfide, the list of target analytes includes carbon monoxide, chlorine, nitrogen dioxide, ammonia, phosphine and hydrogen cyanide.

“Essentially, there is a material that will change color when exposed to a gas,” explained Matthew Chamot, lead mechanical engineer at TDA Research. “Based on that color change, we determine if the gas we’re looking for is present and at what concentration.”

While the device displays the changing color to alert the handler, the sensors also produce auditory and vibratory notifications to alert first responders of present TICs.

The sensors, with platforms that could expand to 15 chemicals, only weigh 70 grams. They are also water and drop-resistant and suitable for use in smoky environments. Of note, the portable devices cost approximately $200 each, significantly differentiating them from similar sensors available in the commercial market.

“The first testing that was done was at the Naval Research Laboratory,” Jones-Holt said. “They were able to obtain the various TICs,” she went on. A report sent back to the TDA team helped with the addition of LED indicators that not only displayed a color change but also the type of chemical detected.

The next set of testing was with the Fairmount Fire Department to gain insight into the usability and effectiveness of firefighters’ everyday gear. “We had them test with their jackets and gloves and all of their equipment,” Chamot explained. “The most difficult thing was probably trying to find a good place where we could mount it, where it would properly sample the gases correctly and also not get in the way or dangle.”