Arsine: The Toxic Gas and the CGA G-16-2018 Standard

Industrial Arsine Gas CGA G 16 2018

Despite sometimes exhibiting a garlic-like odor and being colorless and generally non-irritating, arsine is a flammable and highly toxic gas. Arsine intoxication, which can take up to two days to show any symptoms, comes with headache, nausea, bronzing of the skin, jaundice, shortness of breath, and an agglomeration of other symptoms, with the most severe being the massive destruction of red blood cells resulting in acute kidney failure.

Nonetheless, it is stated in the introduction of CGA G-16-2018: Arsine – 2nd Edition that “arsine can be safely handled if equipment is properly designed, maintained, and employees are trained.” The issue of safely handling arsine, which is formed when arsenic comes into contact with an acid, is important because of arsine’s significance in the semiconductor and metals refining industries.

Specifically, arsine is used as a doping agent for silicon-based solid-state electronic devices, being thermally diffused into the silicon layer using furnaces or through the use of an ion implantation system. Arsine also finds usage in the manufacturing of compound semiconductors, like light-emitting diodes (LEDs), by reaction with a metal organic.

To support the industrial usage of the gas, arsine is shipped as a liquefied compressed gas under its own vapor pressure of 1.515 MPa, abs (219.7 psia). It is also supplied in a gaseous state, diluted with other gases under pressure.

Arsine CGA G-16-2018
Arsine Molecule

At a minimum, CGA G-16-2018 notes that all personnel should have access to an arsine safety data sheet (SDS) and training in the use of the SDS and other reference materials. However, the standard provides and recommends stipulations far beyond this for handling arsine. Since it was written to address the high toxicity and flammability of arsine where the consequences of handling the compressed gas could cause injury, death, and/or facility damage, the CGA G-16-2018 standard provides an understanding of the potential hazards involved in handling arsine and touches upon a breadth of information that can minimize risk potential.

CGA G-16-2018 features guidance for the design of equipment, selection of cylinders and valves, and handling controls and safe practices, as well as safeguards associated with fire protection, gas detection, and ventilation. General guidance is given for the manufacture, purification, and analysis of arsine, but users should be aware that these processes go beyond the scope of the standard.

CGA G-16-2018 was written and published by the Compressed Gas Association (CGA), an ANSI-accredited standards developing organization devoted to the development and promotion of safety standards and safe practices in the industrial gas industry, and it revises the first edition of the same standard for arsine, which was released in 2010.

Any change made to CGA G-16-2018 is underlined in the document’s text. Some highlights include the clarification of publication terminology, changes to the health effect descriptions of arsine exposure, substantial alterations to system temperature control when using arsine for operations, updates to process line control, and new definitions for gas, lethal concentration 50, oxidizer, and lower flammable limit or lower flammability limit (LFL).

CGA G-16-2018: Arsine – 2nd Edition is available on the ANSI Webstore.

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