Applied Nanotech Holdings Inc. develops palladium nanoparticle-based hydrogen gas sensors. The company's MNPS-B hydrogen sensors feature an operating range of 0 ppm to 10,000 ppm, humidity of 0 to 95 percent, and operating temperature of -30C to 110C. The company also designs a hydrogen gas sensor for oil transformer health monitoring. This sensor is capable of measuring dissolved hydrogen in concentrations from 50 ppm to 4,000 ppm.

H2scan Inc. develops hydrogen gas sensing systems for process analysis and safety systems. The hydrogen gas sensors are available as in-line process, intrinsically safe process, fixed area, intrinsically safe area, and explosion proof area types. The majority of the sensors/monitors feature 4-20mA and RS-422 outputs, with the sensors intended for process analysis featuring a sensitivity range of 0.5 percent to 100 percent hydrogen by volume. The sensors for safety systems have a sensitivity range of 10 percent to 125 percent hydrogen lower flammable limit.

Kebali Corp. designs and manufactures MEMS-based hydrogen gas sensors that are temperature and humidity compensated. The sensors feature a range of 0-100 percent LEL, response time of 1 second, a supply voltage of 1.5 volts, an operating temperature range of -55C to 125C, and recovery time of 2 seconds.

NTM Sensors designs and manufactures hydrogen gas sensors that are insensitive to carbon monoxide, methane, and other flammable gases. The sensors can measure hydrogen concentration levels between 0.2 percent to 4 percent in air spanning a range of temperature and humidity variations.

Pem-Tech Inc. develops and manufactures hydrogen sulfide sensors that feature microprocessor-based modular design. Suitable for use in hazardous locations, the sensors are available as electrochemical and solid state metal oxide semiconductor types. All the hydrogen gas sensors feature 4-20mA analog output, 3-digit or LCD display, and detect hydrogen sulfide in parts per million level.

RKI Instruments distributes catalytic and solid state hydrogen-specific sensors for semiconductor, power plant, fuel cell industry, R&D, and gas plant applications. The catalytic hydrogen sensors feature a detection range of of 0 to 100 percent LEL, while the solid state hydrogen sensors have a detection range of 0-2000 ppm. Both sensor types feature explosion proof housing and a 4-20mA transmitter.

Autosampler Guys provides customer support for CTC Analytics products including laboratory hydrogen sensors. Featuring a detection limit of 0.5 percent to 4 percent hydrogen by volume, the sensors are a semiconductor-based, flow-through safety monitor for hydrogen concentration in any GC-oven.

Figaro USA Inc. produces various gas sensors including hydrogen gas sensors and hydrogen sulfide sensors. The hydrogen gas sensors feature a detection range of 50-1,000 ppm, while the hydrogen sulfide sensors have a detection range of 5-100 ppm.

MSA North America develops and manufactures hydrogen sulfide gas sensors that provide a 4-20mA signal and feature a detection range of 0 to 100 percent LEL. The sensors are contained within an explosion-proof housing and used in a number of applications including: chemical plant, drilling rig and platform, electric power, food and beverage, gas collection facility, mud-logging, nuclear, offshore platform, oil/gas distribution, pharmaceutical, sulfur recovery, warehouse, well head, and wastewater treatment facility.

Neodym Technologies designs and manufactures catalytic hydrogen gas sensors/monitors that feature a detection range of 0-25,000 ppm, and output signal of 0-3VDC analog or 4-20mA analog. The sensors are used in fuel cell, and general hydrogen safety applications. The company also produces a catalytic hydrogen-sensing module that has a detection range of 0-40,000 ppm.