Washington (CNN) The White House is reviewing a proposal that environmentalists fear would remove protections for hundreds of threatened species, according to a government database.

The proposal's obscure name -- "Removal of Blanket Section 4(d) Rule " -- refers to protections covering approximately 300 animal and plant species, such as the northern spotted owl and manatee, that are at risk of becoming endangered.

The Fish and Wildlife Service has for 40 years used the blanket rule to cover the majority of threatened species, the category considered at risk of endangerment under the Endangered Species Act.

A spokesman for the Fish and Wildlife Service told CNN that to suggest the rule would overturn the protections is inaccurate. But the spokesman, Gavin Shire, would not elaborate about how that characterization was incorrect or what the proposal calls for, and he declined to provide a copy of the document.

The proposal has not yet been publicly released, and Shire said it is a "draft" that is "under internal review." He said it would be "premature" to discuss the proposal before the department releases it.

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