Human Rights Watch found that in Gaza the IDF used white phosphorus in at least three ways. First, on at least three occasions, Israeli forces air-burst white phosphorus in densely populated areas. On January 15, for example, the IDF air-burst white phosphorus over homes and apartment buildings in the crowded Gaza City neighborhood of Tel al-Hawa, where civilians were living or taking shelter, killing at least four members of one family. White phosphorous shells hit a hospital the same day.

Also on January 15, at least three IDF white phosphorus shells struck the main compound of the UN Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) in central Gaza City, wounding three people and starting fires that gutted four buildings and destroyed more than US$3.7 million worth of medical supplies. UNRWA officials told Human Rights Watch that they had been speaking with Israeli military officers throughout the morning, asking them to halt fire. According to the UN, about 700 civilians were sheltering in the UN compound at the time.

In the attacks on the UNRWA compound and another at the UN Beit Lahiya school, where 1,600 civilians were taking shelter, Human Rights Watch's investigation revealed no apparent military justification for using white phosphorus as an obscurant because Israeli forces were not on the ground in those areas at the time.

Second, the IDF used air-burst white phosphorus on the edges of populated areas, possibly as an obscurant to mask the movement of its forces. In some of these cases, such as in Siyafa village in northern Gaza on January 4 and in Khuza'a village in southern Gaza on January 10 and 13, substantial amounts of burning white phosphorus wedges landed hundreds of meters inside residential areas, killing at least six civilian and wounding dozens. The use of white phosphorus near these residential areas violated the obligation under the laws of war to take all feasible precautions during military operations to minimize civilian harm.

Third, the IDF used air-burst white phosphorus in open areas along the boundary separating Israel and Gaza, Human Rights Watch was not able to investigate whether this use resulted in the destruction of civilian objects in excess of the expected military gain because security concerns prohibited travel to the area.

Select accounts from ‘Rain of Fire'

Ahmad Abu Halima, 22, from Siyafa in northern Gaza, lost his father, three brothers and a sister on January 4 when an artillery shell with white phosphorus exploded inside his house:

"I was talking with my father when the shell landed. It hit directly on my father and cut his head off. The explosion was large and the smell unbearable. It caused a big fire. The pieces [from the shell] were burning and we could not put them out."

Majid al-Najjar from Khuza'a in southern Gaza lost his wife, Hanan, and his children were wounded when a white phosphorus shell landed in his house on January 10:

"First the phosphorus pieces landed. We evacuated the old couple and then the shell hit the house... I saw and I heard the sound of the shell so I went back. I saw the children and men coming out, some of them were injured. My little girl Aya got burned and her right arm was broken. My son Ahmad burned his right foot. My other son Moaz scratched his wrist and head - he is 12 years old."

Ismail Khadr, a 50-year-old farmer, described what happened during an Israeli attack on Khuza'a on January 13:

"When the phosphorus landed we were on an island of smoke. Fires were everywhere and reached waist high. The pieces were like foam. Some of my farm was burned."

UNRWA Gaza Field Administration Officer Scott Anderson, a former US army officer, explained how he contacted the Israeli military as shells landed progressively closer to the UNRWA headquarters on January 15:

"I don't know when exactly the first shell hit us, but the shells were getting close by 8 a.m., and I called the IDF coordination unit at Erez to try to get them to stop it. The pattern of shelling was that it started over the Gaza Training College, in the western part of the UNRWA compound, and then the shelling moved to the west and walked its way over the whole compound. It was hitting the compound itself for around an hour."