Since 1986, the Royal Ontario Museum carries out about six fumigations a year with hydrogen phosphide (phosphine or Phostoxin) for pest control. During routine museum fumigations of exhibit cases, props, and objects, samples of materials were exposed and examined for changes in appearance, odor, handle, and pH. Some cumulative degenerative effects, more severe at high relative humidity, were noted on copper, copper alloys, copper compounds, leather, wool, dyes, drying oils, and ceramics. Few pieces were damaged in proportion to the amount of material exposed, but there was enough damage to cause concern about phosphine's use. Objections are raised as to routine chemical fumigation as the answer to insect control, especially when carried out without documentation. Benzotriazole treatment of copper prior to fumigation protected it only for eight months, after which even the controls showed pinpoint corrosion. Incralac® was more successful, having not failed after two years. Emission of residual phosphine from various materials treated was measured as below detection level. Manufacturer's safety data sheet information on phosphine is given. -- AATA