In a recent survey of an industrial noise problem by the Engineering Experiment Station of The Pennsylvania State College, noise level measurements were made for a large machine shop equipped with 58 high speed multiple-spindle automatic screw machines. The average audio noise level in the shop was found to be 102 db. On occasions, while listening intently to his machine to detect proper or improper operation, the operator would move his head into a region having a noise level of 115 db. Because many new employees at this company had complained of headaches and fatigue in connection with their work, it was suspected that the noise contained a large amount of ultrasonic energy. Also the design of the machines was such as to encourage rather than discourage the production of high frequency noise components. Consequently, an ultrasonic transducer was probed about the machines to determine the particularly noisy locations. Based on the audio and ultrasonic noise levels which were measured, some suggestions were made for noise reduction. The company constructed a sample enclosure to be placed around one of the machines, and a second group of noise measurements were made. Both audio and airborne ultrasonic noise levels showed a reduction of 12 to 15 db. As a result of the decreased noise levels, the company has now taken an interest in fabricating an improved enclosure. An incidental, but quite significant, advantage of the machine enclosure is the confinement of oil mist. Both from the point of view of health and shop cleanliness it is important to reduce the present high loss of cutting oil which escapes in the form of oil mist.