The Obama administration has granted TransCanada permission to build part of the southern portion of the Keystone XL pipeline that would carry oil from the Alberta tar sands through Texas. TransCanada said Tuesday it was still awaiting permits from two other districts of the U.S. Army Corps of Engineers but hoped to begin construction on the pipeline later this summer. President Obama had rejected initial plans for the Keystone XL pipeline earlier this year but later pledged to fast-track approval of the southern portion stretching from Oklahoma to the Gulf Coast. On Tuesday, activists delivered well over 100,000 signatures calling on Environmental Protection Agency head Lisa Jackson to stop the pipeline’s approval. Activists have also pledged a series of nonviolent direct actions against the project this summer, saying the pipeline would poison local communities and destroy the environment.