Public Safety

Toxicity Warning Badge

Originally published in 1996
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GMD Systems of Bacharach, Inc., Pittsburgh, Pennsylvania manufactures and markets toxic gas detection and air sampling devices, with special emphasis on passive "badge" type dosimeters, worn by workers in potentially toxic environments to provide warning of exposure to hazardous chemicals.

For monitoring NASA and contractor personnel exposed to hydrazine and monomethyl hydrazine (MMH), NASA contracted with GMD Systems for development of a colorimetric gas monitoring dosimeter. Hydrazine and MMH are hyperbolic fuels that ignite on contact with an oxidizer; typical risk areas where exposure monitoring is required include facilities where the fuels are produced and facilities where workers are engaged in assembly and operational handling of spacecraft, missiles and aircraft auxiliary power units in which the fuels are used.

GMD Systems developed a reliable monitoring dosimeter for NASA, then modified the NASA technology to create a new commercial product, the GMD 530 Series Hydrazine Badge. The commercial version is used in chemical manufacturing, industrial cleaning applications and in areas where hydrazine is used as an oxygen scavenger, such as boiler feed water in the electric industry.

The 530 series badge has two separate paper tape chemistries in one badge; a pair of circular windows in the badge allow each tape to be exposed and observed. In the presence of either hydrazine or MMH, both tapes change colors, providing an immediate visual alarm.

In both cases, the density of the color stain increases in proportion of the hydrazine/MMH in the air and the total time of exposure. The system includes two types of pocket-size estimator cards (Dose Estimator Units), one for each substance. A supervisor uses the estimator to match the color of an exposed badge with a set of color standards for the particular substance involved; the standards are shown on the estimator card for quick reference. The color matching serves as a basis for immediate, accurate estimation of the level of exposure.

Abstract
Kennedy Space Center contracted GMD Systems, Inc., now Bacharach, Inc., to design a system for monitoring personnel exposure to hydrazine and monomethyl hydrazine, two dangerous gases which ignite on contact with an oxidizer. GMD developed a reliable colorimetric gas monitoring dosimeter for NASA, then modified it to create the commercial GMD 530 Series Hydrazine Badge. The badge has two separate paper tape chemistries which change color when the gases are detected, the density of the color being in proportion to the time of exposure and amount of gas in the air. The badge is used in facilities where hypergolic fuel is produced or used in support of space vehicles, satellites, missiles, and military aircraft auxiliary power units.
Badge hung on a pipe for use as a low-cost leak detector

The badge offers secondary utility as a low-cost leak detector hung on suspect pipes or valves.

Two Hydrazine badges show the reaction when exposed to hydrazine, the badge has turned orange and yellow

GMD Systems' Hydrazine Badge changes color when its wearer is exposed to a chemical containing a hydrazine component.