Environmental justice is a contentious, subjective, and squishy topic. It's often a leading factor in lawsuits after the environmental damage has been done — but historically it has been notoriously difficult to incorporate environmental justice into regulations aimed at preventing disproportionate burdens of environmental harm on vulnerable or marginalized populations.
On July 22, 2010, the US EPA issued an interim guidance document  (Plan EJ 2014) to help agency staff proactively incorporate environmental justice into environmental regulations. This document is intended for internal use by EPA staff, but it's open to public comment (no comment deadline).
This 55-page guidance document is thoroughly bureaucratic — for instance, Appendix B is a strikingly convoluted flow chart for the suggested agency decision-making process. Still, it can be a useful resource for reporters who seek to understand and highlight potential environmental justice issues unfolding at the national, regional, or state level.
Plan EJ 2014 currently is being assessed by the National Environmental Justice Advisory Council  (NEJAC) — a council assembled by EPA in 1992 to address environmental justice issues.
EPA's Office of Enforcement and Compliance Assurance also has developed an Environmental Justice Strategic Enforcement Assessment Tool  (EJSEAT), to "consistently identify areas with potentially disproportionately high and adverse environmental and public health burdens. EJSEAT uses 18 select federally-recognized or managed databases and a simple algorithm to identify such areas".
EJSEAT datasets are divided into four indicator categories: environmental, human health, compliance, and social demographics. Each category includes a list of specific data types — so when you see these data types mentioned in environmental databases, examining them could help you identify environmental justice concerns.
According to Greenwire (republished in the New York Times ), the goal of EJSEAT is to develop a "national database that will identify small tracts of people as unfairly affected over the years. Officials can take the score into consideration while making land-use and permit decisions, reducing chances of human judgment errors." Also, "this tool, currently under review, is being deployed in a limited manner in regional environment offices."
This context can inform your searches of current EPA rulemakings. The EPA rulemaking gateway  is a portal to the agency's current priority rulemakings under development.
Environmental justice can be anyone's political football. One current high-profile rulemaking process which raises thorny environmental justice issues is EPA's attempt to regulate greenhouse gases. A March 2010 report from the Affordable Power Alliance (which some say  is an astroturfing operation funded by fossil fuel interests) contends that EPA's December 2009 "Endangerment Finding" on greenhouse gases could end up having "especially severe impacts on low-income groups, the elderly, African Americans, and Hispanics."
The environmental advocacy group Public Employees for Environmental Responsibility has voiced scathing skepticism  of the current EPA environmental justice push. "Rather than directly confront environmental justice challenges, the Environmental Protection Agency has issued internal guidance that is so convoluted and vague that it will stymie effective action. … At the same time, EPA is allowing affirmative approaches to relieving the air pollution burden on the urban poor to languish." PEER press: Kate Hornyan, 202-265-7337.
PEER referred to a June 2010 EPA Office of Inspector General report (10-P-0154) which found that EPA's Urban Air Toxics strategy (an EPA program launched in 1999 to evaluate and regulate air toxics, especially in urban areas) was far behind schedule.