根据美国矿山安全与健康管理局(MSHA)在2014年10月末的报道,在新的粉尘规定颁布后的头2个月内,其采集的有效呼吸性粉尘样本中,大约有99%都达到了规定值。而在这之前他们还担心采矿业可能不太容易达到他们提出的新要求。这个新规定的生效时间为2014年8月1日,将原来的地下和露天煤矿中的粉尘总量标准中的暴露限值从2.0 mg/m3空气降低到1.5 mg/m3空气;还把地下煤矿及尘肺病矿工的吸入空气限值从1.0 mg/m3 According to a report by the MSHA in late October 2014, about 99% of the samples of available respiratory dust collected during the first two months after the new dust regulation was enacted Prescribed value. And before that they also worried about the mining industry may not be easy to meet their new demands. The new regulation came into effect on August 1, 2014, reducing the exposure limit of 2.0 mg / m3 air to 1.5 mg / m3 of air in the original total dust and dust content standards for underground and open pit mines; And inhaled air for miners with a pneumoconiosis limit of 1.0 mg / m3