For a second time, the Environmental Protection Agency has turned aside a request to ban the use of lead in hunting ammunition.

The request was made recently by the Center for Biological Diversity and a host of other environmental groups.

In response to the denial, CBD has vowed the sue EPA.

"We look forward to putting this issue before a court, since the law is very clear that EPA has the responsibility to protect wildlife and people from toxic lead exposure," said Jeff Miller, in charge of the center's anti-lead campaign. "The EPA never evaluated the merits of regulating toxic lead ammo, nor has a court ruled on its authority to act under the federal toxics law. Well, that will soon change."

The group in March submitted a 107-page petition to the EPA, asking the agency to ban the use of lead ammunition.

This is the second time the EPA has turned aside such a request, the first in 2010 when the center also asked the agency to ban the use of lead in fishing sinkers.

The EPA put that idea up for public comment, receiving nearly 7,000 comments, most of them dealing with the issue of lead in ammunition.

The EPA denied the request in November 2010, saying there wasn't sufficient justification for the ban.

Miller derided the EPA for its decision, calling it a "national tragedy the EPA can easily put an end to, since there are plenty of safe, available alternatives to lead ammo."

In rejecting the petition, EPA said it would not review an "identical petition," and said it cannot regulate lead ammunition.