We have used gas chromatography-mass spectroscopy (GCMS) to study the decomposition of TEA (tert-butylarsine, H2AsC(CH3)(3)) in storage containers at room temperature. Over a four-week period, as much as 1% of the TEA decomposed to arsine and isobutane in a stainless-steel bottle, Several freeze-thaw purification schemes were tested. Use of a liquid-nitrogen bath left a substantial amount of arsine and isobutane in the bottle, while an ice water bath removed all of the arsine but left residual isobutane, Evacuation of the storage container at room temperature removed both arsine and isobutane: to below the GCMS detection limits. However, this approach did lead to significant TEA loss. Storing TEA in a Teflon-lined bottle and in a high-surface-to-volume stainless-steel container did not change the decomposition rate measurably, suggesting that stainless-steel surfaces do not promote TEA decomposition.