CAMBRIDGE, Mass. —  A lawyer said an MIT fraternity involved in a prank that left two environmental cleanup volunteers severely injured has agreed to pay the victims a six-figure settlement.

The victims’ lawyer, John Barton, said Tau Epsilon Phi has agreed to settle with Thomas Soisson and Kate Nardin after a member tossed sodium metal into the Charles River.

Barton said Soisson and Nardin suffered severe burns in April 2008 when the two deposited the sodium metal in a plastic trash barrel.

MIT students have an annual tradition of throwing a lump of the substance from the school’s chemistry labs into the river.

Fraternity member Bhaskar Mookerji pleaded guilty to disorderly conduct and an environmental pollution violation.