Low-level styrene exposure and color vision in Swedish styrene workers

Styrene exposure and color vision for 108 workers (21-65 years) was studied at Swedish reinforced plastic plants. Acute exposure was measured at work. Data on past exposures and personal background data were collected by questionnaire. Current exposure varied between 0.3 and 96 mg/m3. Cumulative past exposures varied from 18 to 4455 mg years/m3, and an index of lifetime weighted average exposure (LWAE) varied from 5 to 129 mg/m3. Color vision was tested using the Lanthony D15 desaturated panel binocularly without prior training in conditions with ample light (1400 lx). Color vision was slightly correlated to LWAE (r = 0.188, p = 0.052). Workers were divided into two exposure groups according to LWAE. Analyses of variance revealed effects on the Vingrys' color vision confusion index (F = 6.04; p = 0.016) and total error (F = 6.296; p = 0.014). This study thus indicates that styrene exposure even at levels below the current Swedish OEL of 20 mg/m3 may affect color vision negatively.