Flags are lowered to half mast in West, Texas, the United States, April 20, 2013. The Authorities of the city of West, the U.S. state of Texas, on Saturday declared to impose curfew while allowing some of the evacuated residents to return home in the afternoon, more than two days after a powerful explosion at a local fertilizer plant that almost razed the town. (Xinhua/Zhang Yongxing)

Rescue vehicle are seen in West, Texas, the United States, April 20, 2013. The Authorities of the city of West, the U.S. state of Texas, on Saturday declared to impose curfew while allowing some of the evacuated residents to return home in the afternoon, more than two days after a powerful explosion at a local fertilizer plant that almost razed the town. (Xinhua/Zhang Yongxing)

Police vehicle are seen in West, Texas, the United States, April 20, 2013. The Authorities of the city of West, the U.S. state of Texas, on Saturday declared to impose curfew while allowing some of the evacuated residents to return home in the afternoon, more than two days after a powerful explosion at a local fertilizer plant that almost razed the town. (Xinhua/Zhang Yongxing)

A spokeman declares to impose curfew in West, Texas, the United States, April 20, 2013. The Authorities of the city of West, the U.S. state of Texas, on Saturday declared to impose curfew while allowing some of the evacuated residents to return home in the afternoon, more than two days after a powerful explosion at a local fertilizer plant that almost razed the town. (Xinhua/Zhang Yongxing)

Workers work in West, Texas, the United States, April 20, 2013. The Authorities of the city of West, the U.S. state of Texas, on Saturday declared to impose curfew while allowing some of the evacuated residents to return home in the afternoon, more than two days after a powerful explosion at a local fertilizer plant that almost razed the town. (Xinhua/Zhang Yongxing)

A woman writes a check for donation in West, Texas, the United States, April 20, 2013. The Authorities of the city of West, the U.S. state of Texas, on Saturday declared to impose curfew while allowing some of the evacuated residents to return home in the afternoon, more than two days after a powerful explosion at a local fertilizer plant that almost razed the town. (Xinhua/Zhang Yongxing)

Local residents comfort each other after hearing the news of imposing curfew in West, Texas, the United States, April 20, 2013. The Authorities of the city of West, the U.S. state of Texas, on Saturday declared to impose curfew while allowing some of the evacuated residents to return home in the afternoon, more than two days after a powerful explosion at a local fertilizer plant that almost razed the town. (Xinhua/Wang Lei)

Local residents listen to the news of imposing curfew in West, Texas, the United States, April 20, 2013. The Authorities of the city of West, the U.S. state of Texas, on Saturday declared to impose curfew while allowing some of the evacuated residents to return home in the afternoon, more than two days after a powerful explosion at a local fertilizer plant that almost razed the town. (Xinhua/Wang Lei)

A policeman cordons off a road leading to the fertilizer plant in West, Texas, the United States, April 20, 2013. The Authorities of the city of West, the U.S. state of Texas, on Saturday declared to impose curfew while allowing some of the evacuated residents to return home in the afternoon, more than two days after a powerful explosion at a local fertilizer plant that almost razed the town. (Xinhua/Wang Lei)

A flower shop is closed due to the blast of the fertilizer plant in West, Texas, the United States, April 20, 2013. The Authorities of the city of West, the U.S. state of Texas, on Saturday declared to impose curfew while allowing some of the evacuated residents to return home in the afternoon, more than two days after a powerful explosion at a local fertilizer plant that almost razed the town. (Xinhua/Wang Lei)

Local residents listen to the news of imposing curfew in West, Texas, the United States, April 20, 2013. The Authorities of the city of West, the U.S. state of Texas, on Saturday declared to impose curfew while allowing some of the evacuated residents to return home in the afternoon, more than two days after a powerful explosion at a local fertilizer plant that almost razed the town. (Xinhua/Wang Lei)

Work staff cordon off a road leading to the fertilizer plant in West, Texas, the United States, April 20, 2013. The Authorities of the city of West, the U.S. state of Texas, on Saturday declared to impose curfew while allowing some of the evacuated residents to return home in the afternoon, more than two days after a powerful explosion at a local fertilizer plant that almost razed the town. (Xinhua/Wang Lei)

 A fireman drives to the fertilizer plant in West, Texas, the United States, April 20, 2013. The Authorities of the city of West, the U.S. state of Texas, on Saturday declared to impose curfew while allowing some of the evacuated residents to return home in the afternoon, more than two days after a powerful explosion at a local fertilizer plant that almost razed the town. (Xinhua/Wang Lei)

 A local residents listens to the news of imposing curfew in West, Texas, the United States, April 20, 2013. The Authorities of the city of West, the U.S. state of Texas, on Saturday declared to impose curfew while allowing some of the evacuated residents to return home in the afternoon, more than two days after a powerful explosion at a local fertilizer plant that almost razed the town. (Xinhua/Wang Lei)

 Local residents comfort each other after hearing the news of imposing curfew in West, Texas, the United States, April 20, 2013. The Authorities of the city of West, the U.S. state of Texas, on Saturday declared to impose curfew while allowing some of the evacuated residents to return home in the afternoon, more than two days after a powerful explosion at a local fertilizer plant that almost razed the town. (Xinhua/Wang Lei)