Two environmental groups are seeking court-ordered deadlines for EPA to finish long-running reviews of several air quality standards.

In a lawsuit filed today, the Center for Biological Diversity and the Center for Environmental Health ask a judge to set a timetable for completing the assessments of the secondary “public welfare” standards for sulfur dioxide, nitrogen oxides and particulate matter. Secondary standards are aimed at protecting plants, animals and ecosystems, rather than human health.

The agency is currently pursuing that task in a combined package that dates back to 2013. Under a legally binding Clean Air Act schedule, however, it should have been completed years ago, the suit alleges.

In an email today, an EPA spokesperson declined to comment.

The three pollutants are among a half-dozen covered by National Ambient Air Quality Standards that EPA is supposed to review every five years to keep them in line with the latest research.

Most of the agency’s attention is focused on the primary standards, which are geared to protecting public health. But in the suit, the challengers say that evidence of the harmful environmental effects of all three pollutants has grown since EPA last revisited the secondary standards. For sulfur dioxide, for example, the science “now suggests that there is a causal relationship between sulfur deposition and changes in biota, which can alter growth, productivity, species physiology and richness, and biodiversity in wetland and freshwater ecosystems,” the suit says.

Read the full piece.