The Obama administration extended a special immigration status on Friday to Haitians living illegally in the United States that protects them from deportation for 18 months and allows them to work here.

Calling the aftermath of the earthquake “a disaster of historic proportions,” the secretary of homeland security, Janet Napolitano, said she was granting the designation, known as temporary protected status, for Haitian immigrants because their safety would be at risk if they were deported.

Administration officials said the special status would cover at least 100,000 Haitians believed to be living in the United States illegally, as well as about 30,000 Haitians who had been ordered deported. Haitians who receive the temporary status will be able to obtain documents allowing them to live here and work legally.

The administration’s decision followed a rising chorus of calls for the temporary status after the earthquake on Tuesday. On Friday, 80 representatives and 18 senators, including Democrats and Republicans, sent appeals to the administration to grant the status, as did the conference of Roman Catholic bishops.