The public will get one more chance to discuss cleanup efforts at Site 300 before the U.S. Department of Energy settles on a plan to deal with groundwater contamination from radioactive materials and other toxic chemicals.

The 7,000-acre explosives test range just west of the proposed Tracy Hills development includes pits filled with radioactive waste from non-nuclear test explosions. Some of the site’s groundwater is also contaminated with solvents and other chemicals used at the site since it opened in 1955.

The Department of Energy is nearly finished with its plan to clean up those pits and treat the contaminated groundwater. But a Livermore-based group that tracks activities at Lawrence Livermore National Laboratory and Site 300 hopes the public will tell the energy department and the U.S. Environmental Protection Agency that its cleanup plan is inadequate.

“If the community doesn’t speak out and require the cleanup plan be improved, the EPA doesn’t have any basis to believe the community wants more,” said Marylia Kelley, executive director of Tri-Valley Communities Against a Radioactive Environment.

The comments on the plan will be included in a “record of decision,” which will spell out the energy department’s responsibilities as it cleans up the site. The department will take written comments on the plan through July 25.

The “Site-wide Proposed Plan” explains where contamination is and how it will be dealt with. For example, a dump at the northwest corner of the site has caused groundwater contamination during heavy rains, when the water table rises and makes contact with depleted uranium and tritium from explosives tests. That has created a plume of tainted groundwater — contaminated with radioactive tritium — that stretches across the northern part of the site.

Energy officials propose digging trenches and drains around the dumps and pumping and treating groundwater, but it would not remove any of the radioactive materials from the pits.

“If you look at this proposed plan, it doesn’t require any excavation in the pits at all,” Kelley said, adding that the trenches and drains will help but won’t be enough to guarantee that groundwater won’t be contaminated in the future.

As of press time, a laboratory spokeswoman had not returned calls seeking comment.