Photovoltaic specialty materials safety

The PV industry uses an assortment of specialty gases and liquids many of which are reactive, pyrophoric or highly toxic, requiring care in handling and special training for emergencies. In addition, some of the PV facilities are being located in countries or regions which have not yet developed the supply or EHS support infrastructure for these materials. Regional expertise is limited, even in the US where facilities are sometimes located in rural areas. The dominant PV technology is crystalline which typically uses silane, phosphine, trimethylboron and ammonia in the process. These gases have a wide variety of hazard characteristics that must be controlled. The dominant specialty gas used is silane, which many users assume will always ignite during an intentional or accidental release. Unfortunately this is not always the case. Tragically, the PV industry suffered two fatal silane accidents in 2005 and 2007 and there have also been numerous fires and explosions. The Integrated Circuit (IC) industry experienced similar problems in the 1970's and 1980's. From 1985 through the 1995, a series of silane technical and safety seminars were conducted in the United States and Europe. These created awareness of potential problems and helped to drastically reduce the number of incidents and/or their severity by establishing industry safe practices and regulations throughout the industry. The PV industry is relearning these lessons learned. This presentation will be a review of the hazard characteristics of the key metal hydride gases used in PV manufacturing. It will also summarize significant incidents involving silane.