Manufactured fibers derived from natural origins include viscose rayon, azlon, and polylactic acid (PLA). A 2-year study was conducted to document any changes these fibers undergo as a result of exposure to various environmental conditions. Fabric swatches representing each fiber type were exposed to freshwater, saltwater, heat, cold, ultraviolet light, or composter conditions. Fibers from the swatches were periodically analyzed using polarized light microscopy and Fourier transform infrared microspectroscopy. Fiber solubility and melting-point behavior were measured every 6 months. Except for the complete degradation of viscose rayon in the composter, saltwater, and freshwater environs, no changes in the optical properties, infrared spectra, solubility, or melting points of the remaining fibers in any of the environments were observed. However, microscopic morphological changes were observed in fibers from two azlon swatches submerged in freshwater and saltwater, two PLA swatches exposed to ultraviolet light, and two viscose rayon swatches exposed to ultraviolet light.