The use of photocell plethysmographic instruments to test for Raynauds or vibration syndrome in workers using pneumatic chisels was investigated. The hand was placed in ice water to restrict blood flow. Recovery of vascular flow to the hand being examined was measured by placing a finger in a beam of light and measuring changes in light transmission (changes in tissue transparency) with a photocell. The hand afflicted with vibration syndrome or the dominant hand in unafflicted subjects was tested. Time to 90 percent vascular recovery was measured. Results for chipping workers, many with other signs of vibration syndrome, were compared to those for comparison workers not exposed to vibration. In the ring finger of comparisons and asymptomatic workers, 70 percent recovered to 90 percent of baseline flow by 150 seconds. In workers with symptoms of tingling, numbness, or both, 55 percent recovered to 90 percent of baseline flow by 150 seconds. In workers with stages 1 through 3 blanching, only 20 percent recovered to 90 percent of baseline flow within 150 seconds. Results for the middle finger were similar, with 60, 50 and 30 percent of comparisons, mild symptomatic workers and those with finger blanching recovering 90 percent of baseline vascular flow within 150 seconds. The authors conclude that the presence of vibration syndrome is related to prolonged recovery time of the blood flow after immersion of the opposite hand in ice water. However, the test as presently performed does not allow clear distinctions between subjects with and without vibration syndrome and is probably not useful in the clinical diagnosis of the condition. Improvements which could be made in testing procedures are recommended.