Here’s the abstract for the CRS report Temporary Protected Status: Overview and Current Issues (Jan. 17, 2018 RS20844):
When civil unrest, violence, or natural disasters erupt in countries around the world, concerns arise over the ability of foreign nationals in the United States from those countries to safely return. Provisions exist in the Immigration and Nationality Act (INA) to offer temporary protected status (TPS) and other forms of relief from removal under specified circumstances. The Secretary of Homeland Security has the discretion to issue TPS for periods of 6 to 18 months and can extend these periods if conditions leading to TPS designation do not change. Congress has also provided TPS legislatively. A foreign national who is granted TPS receives a registration document and employment authorization for the duration of a given TPS designation.
The United States currently provides TPS to approximately 437,000 foreign nationals from 10 countries: El Salvador, Haiti, Honduras, Nepal, Nicaragua, Somalia, South Sudan, Sudan, Syria, and Yemen. TPS for Guinea, Liberia, and Sierra Leone expired in May 2017, but certain Liberians maintain relief under an administrative mechanism known as Deferred Enforced Departure (DED). Since September 2017, the Secretary of Homeland Security has announced plans to terminate TPS for four countries—El Salvador, Haiti, Nicaragua, and Sudan—and extend TPS for South Sudan. No decision about Honduras was made by the statutory deadline in November 2017, thus automatically extending that country’s designation for six months.
There is ongoing debate about whether migrants who have been living in the United States for long periods of time with TPS should receive a pathway to legal permanent resident (LPR) status. In addition, Venezuela’s political and economic strife have prompted some U.S. lawmakers to call for its designation for TPS.