The Environmental Protection Agency is planning to retain current federal limits on industrial soot pollution, spurning tighter limits that environmentalists and the agency’s own staff said were needed to protect health.

In a proposed rule Tuesday, the EPA said it would retain national ambient air quality standards for fine particulate matter, or PM2.5, which the agency has said poses serious risks to human health and welfare. The fine particles are commonly known as soot, and when inhaled, they can cause increased respiratory symptoms, such as difficulty breathing, nonfatal heart attacks, and premature deaths in people with lung or heart disease, according to the agency.