This report provides an evaluation by members of the Hydrogen Safety Panel (HSP) of the June 1, 2019 hydrogen release incident at the Air Products and Chemicals Inc. (Air Products) hydrogen trailer transfill (transfill) facility located in Santa Clara, California. This review was requested by the California Energy Commission (CEC) in May 2020 and examines data from Air Products, and the Santa Clara Fire Department to provide an HSP perspective on the incident cause, response, and recommended follow-up actions. 

This Technical Memorandum was originally prepared as an Annex on the topic of Hydrogen Embrittlement for the AIAA Guide to Safety of Hydrogen and Hydrogen Systems (G-095-2004), then in revision [1]. The Guide establishes a uniform NASA process for hydrogen system design, materials selection operation, storage and transportation, and represents a broad collection of aerospace acumen.

In collaboration with Parker Hannifin Corporation, the Fire Safety Branch of the FAA conducted testing to evaluate the effects of three potential failure conditions of hydrogen proton exchange (or polymer electrolyte) membrane fuel cell stacks supplied by Nuvera Fuel Cells. The three conditions examined were a loss of coolant to the stack, short circuit, and a crossflow condition.