BISBEE — Construction of a border fence in the San Pedro Riparian National Conservation Area can be restarted, but it is not clear when the work will actually begin.

Homeland Security Secretary Michael Chertoff exercised his authority Monday to make the fence exempt from the law because further delays in its construction would present a risk to national security.

Veronica Valdes, spokeswoman for the Department of Homeland Security, said she does “not have a specific date for when the work is going to start up.”

Carrie Templin, a public affairs officer with the Bureau of Land Management, which controls the San Pedro Riparian National Conservation Area, also does not know when the work will begin.

“BLM has been cooperating with everyone to the best of their ability and will continue to do so, but as far as what that next step is or when construction will restart, I don’t think we know the answer to that question,” she said.

Greta Anderson, who has participated in conservation efforts in the San Pedro River area, said she thinks construction could get under way very soon.

Anderson is concerned about the impact the fence will have on the environment.

She said she would like to see government officials “actually consider the sensitive wildlife habitat along the border and modify their proposals to reflect those values.”

“We are mourning the San Pedro River,” she said. “It’s really frightening.”

Valdes said that just because Chertoff took the action regarding the border fence construction, it doesn’t mean the department will compromise its commitment to responsible environmental stewardship.

She noted there is a “very high” amount of illegal traffic in the area, and the activity jeopardizes the department’s ability to secure the border and also causes “severe and profound” impacts on the environment.

“The illegal roads divert the normal flow of water, and the illegal entrants also leave behind a lot of trash and a concentration of human waste in the area,” she said.

“This fence will not only secure our borders and lessen that security risk, but it will also be a significant improvement to the environment in that area, and it will increase the public’s ability to enjoy it as a resource.”

Tricia Gerrodette, a community and environmental activist who lives in Sierra Vista,  said  the  impact  of illegal immigration traffic may be bad for the environment, but the impact of the fence is even worse.

“It is unfortunate, I think, that the government has the power and is choosing to exercise the power to restart fence construction without doing an appropriate and adequate environmental review,” she said. “Lots of creatures migrate across the border. Some of them fly, and they will be less impacted by it than others. Some of them use the ground, and it will definitely be harmful to them,” she added.