little evidence little evidence little evidence little evidence the Occupational Safety and Health Administration’s report date back to the 1970s psychological problems little evidence little evidence audible subharmonic byproducts of ultrasound little evidence little evidence OSHA Technical Manual on Noise & Hearing Conservation www.osha.gov/dts/osta/otm/new_noise/#noisecontroleng little evidence little evidence little evidence audible subharmonic byproducts of ultrasound OSHA Technical Manual: Noise little evidence little evidence little evidence audible subharmonic byproducts of ultrasound audible subharmonic byproducts of ultrasound little evidence audible subharmonic byproducts of ultrasound date back to the 1970s little evidence OSHA Technical Manual on Noise & Hearing Conservation audible subharmonic byproducts of ultrasound little evidence audible subharmonic byproducts of ultrasound little evidence little evidence Technical Manual. audible subharmonic byproducts of ultrasound date back to the 1970s little evidence little evidence little evidence little evidence