HAMMOND | The newest, most sophisticated mobile laboratory in the U.S. Environmental Protection Agency fleet arrived Friday afternoon at the south side scene of last month's underground petroleum pipeline leak.

Once instruments aboard the facility are calibrated, technicians will begin taking samples in nearby homes to determine levels of any toxic or carcinogenic substances released from a crack in the BP oil line at 175th Street and White Oak Avenue, officials said.

The company replaced curved sections of the pipeline at White Oak and Walnut avenues last week, and crews poured fresh asphalt on the Walnut Avenue intersection Friday to complete repairs there.

Remediation of the White Oak Avenue area will take a little longer, officials said.

About 420 tons of soil already have been removed from easements and yards near the intersection, according to EPA, and more than 150,000 gallons of oily liquid have been pumped out and taken away, with more to come.

More than 50 well-points in triple rows have been sunk into the ground and pavement around 175th Street and White Oak Avenue to pull out groundwater and to measure potential contamination.

New segments of 30-inch water main are stacked nearby, awaiting the completion of soil removal so about 200 feet of the line – supplying fresh water to the city's south side, as well as Griffith, Highland and Munster – can be replaced, along with 6- and 8-inch water lines, as well as service lines to several homes.

The water mains are being replaced as a precaution in case lines or connecting gaskets may have been contaminated by leaking petroleum, Water Department officials said. No such problem has been detected.

All of the work is to be paid for by BP, according to an EPA administrative order filed Aug. 18 under authority of the national Clean Water Act.

The remediation work is supposed to be completed by Sept. 15, according to the EPA order, but federal and Indiana Department of Environmental Management officials said Friday the timetable could be modified because of conditions at the site.

In addition to EPA, IDEM and the Hammond Department of Environmental Management, officials with the federal Agency for Toxic Substances and Disease Registry also were on scene Friday, talking to neighborhood residents about their health.

Officials said the intersection of 175th Street and White Oak Avenue likely will remain closed to traffic for several more weeks.