Residents living along a stretch of Central Oahu that includes Wahiawa and Kunia are most at risk from pollution from abandoned hazardous waste sites. High levels of lead paint, a suspected carcinogen, plague communities in Palolo Valley, Waipahu and large swaths of Kaimuki. And Waianae

and Nanakuli, which have high levels of poverty, host much of the island’s hazardous waste.

This is just a snippet of the information that legislators, government officials and local residents can discern from a new online mapping tool developed by the U.S. Environmental Protection Agency to promote environmental justice.

The tool, called EJScreen, provides detailed information about pollution, traffic congestion, toxic spills, air quality, sources of water pollution and other environmental hazards, and combines this with census data to identify areas where there are high levels of poverty or where certain ethnic groups are concentrated.

“Environmental justice is making sure that no community is overburdened by environmental hazards or potential risks,” said Laura McIntyre, program manager for the Hawaii Department of Health’s Environmental Planning Office. McIntyre, along with Charles Swanson, an environmental protection specialist at the EPA, spent last week showcasing the mapping tool to the staffs of local lawmakers and state and county government agencies.

Ideally, the data will be used by policymakers when making decisions about where to locate new power plants, landfills and highways, or where to concentrate environmental cleanup efforts. The information can also be used by land-use and planning agencies in making various permitting decisions.

The tool is particularly useful because it combines environmental data with national census data, which in the past hasn’t been very user-friendly, said McIntyre.

In addition to the environmental hazard indicators already built into the map, the EPA plans to soon input air quality data that can identify pockets of pollution, as well as communities’ lifetime cancer risk from inhaling air toxins.

The sophisticated mapping tool can break down information by district to give legislators a better understanding of the issues affecting their communities. EJScreen can also generate reports that show how Hawaii compares with other states and national averages.

Not surprisingly, the map shows that Oahu traffic congestion ranks as some of the worst in the nation.

McIntyre said that users can also input their own data sets into the map, such as the locations of drinking wells. For sensitive data, government agencies can keep the sets private.

The EPA spent five years developing the tool. The effort stems from a 1994 executive order issued by then-President Bill Clinton requiring federal agencies to collect data on environmental hazards that are disproportionately affecting minority and low-income populations.

The environmental justice movement picked up momentum in the 1980s when anger mounted about disproportionate levels of toxic dumps and industrial sites being placed in poor and minority communities.

One of the more high-profile cases involves a stretch of land between Baton Rouge, La., and New Orleans, where numerous industrial plants were built. Cancer clusters among the population led to the area being dubbed “Cancer Alley.”

Locally, lawmakers and community leaders have protested adding additional power plants and waste dumps along the Waianae Coast, where the population is heavily Native Hawaiian. Last year, Councilwoman Kymberly Pine, who represents the region, successfully sponsored a series of “environmental justice” bills that targeted illegal dumping and grading in the area.