Complaints of photosensitivity in ultraviolet (UV) cured ink workers (SIC-2899) were investigated. Four white males, aged 26 to 52 years, were studied. Their jobs were to weigh, mix, or mill the UV cured ink. Clinical characteristic, after sun exposure were burning or smarting and erythema and swelling, with durations up to several days. Eczematous dermatitis, an allergic contact sensitization to acrylates, was seen in two of the workers. The UV absorption spectra of all ingredients of the ink were determined by a spectrophotometer. Ingredients absorbing UV radiation over 290 nanometers (nm) were evaluated for phototoxicity in an Ehrlich ascites cell system. Photopatch testing was performed on three employees complaining of photosensitivity and four free of photosensitivity. In-vivo phototoxicity and photoprotection tests were done. Protection was patch tested with 5 percent p- aminobenzoic-acid (150130) and 10 percent sulisobenzone (4065456). Photoinitiators found to absorb UV radiation above 250nm were benzophenone (119619), thioxanthone (492228), 2,2- diethoxyacetophenone (6175457), Michler's ketone or 4,4'- bis(dimethylamino)benzophenone (90948). Phototoxicity assay showed that Michler's ketone, thioxanthone, and the two absorbers were phototoxic. Only the absorbers proved phototoxic in in-vivo patch tests. Phototesting demonstrated diphasic reactions in both sensitive and non sensitive employees. The prior application of 5 percent p-aminobenzoic-acid provided partial protection, but 10 percent sulisobenzone completely suppressed the phototoxic response. The authors suggest that a 10 percent sulisobenzone preparation may be a useful sunscreen for use in accidental skin contamination.