Thousands of pieces of equipment and machinery that produce hazardous noise levels are used in the manufacturing, construction and service industries in the United States of America. Often management of noise hazards has relied on providing hearing protection to workers, implementing hearing conservation programs, and training workers on the proper use and wear of hearing protection. To be effective, this strategy requires high levels of interaction and coordination from workers, supervisors and safety professionals. Furthermore, the worker's primary workplace responsibilities and activities may distract them from consistent and proper hearing protection use. Although engineering controls are frequently a better solution, the reality is that cost-conscious employers are unlikely to have a noise-control expert on staff to facilitate implementing such measures.
The lack of effective noise controls may be a reason that noise-induced hearing loss is still one of the most prevalent occupational health concerns in the United States of America, with the Agriculture, Construction and Mining Industries most consistently leading in prevalence. In fact, approximately 22 million workers are exposed to hazardous noise levels in the United States. Exposures in the noisiest industries can be quite high due to equipment noise emissions. For instance, heavy equipment like piling equipment, road milling machines and drill rigs can create sound levels in excess of 110 dB(A), while other more common equipment like circular saws, loaders and leaf blowers can have sound power levels between 100 and 110 dB(A) as specified in EU Directive 200/14/EC. Despite potentially dangerous noise emissions in the workplace, engineering controls for noise have not been universally adopted; some of the reasons for this are explored below.