In my mind's eye 9/11 exists in monochrome - white and black - with the occasional red-orange glow. I still feel the granular particles in my eyes and nose. I still remember the sensation of walking over the powdered remains of the Twin Towers, several centimetres above the pavement; sometimes cushioned, almost floating, and sometimes, where fire-fighters had doused flames, sliding through a slick sludge.
I arrived at Ground Zero just before midnight on 9/11. The sky was dark but the surrounding streets were bathed in a harsh white halogen glow so bright that it was almost like daylight. Everything was caked in grey dust and sheets of paper were everywhere, fluttering on updrafts or plastering the facades of buildings. The combination of light, dust and paper made everything under the sky look white - apart from the black pit of Ground Zero itself. Standing at the edge of the crumbled remains of lives lost, I peered into a vast darkness studded with the occasional flame, or maybe they were shards of red-hot metal. It felt like I was looking at hell.
I was in New York as a rabbinical student and had come to Ground Zero as a chaplain. Having spent the morning mesmerised by the TV pictures I had gone to volunteer. My first stop had been a mid-town hospital preparing to receive casualties. Around me wandered streams of nurses and doctors waiting for causalities who never came. There was an ambulance crew who arrived, caked in powderised masonry, but no injured. There was nothing to do.
I moved on to Chelsea Piers, a complex of warehouses on the West Side of Manhattan; the word was that the injured were being taken there. One warehouse had been turned into suite of makeshift emergency surgery beds with anaesthetists, surgeons, nurses, all gowned-up and ready to go. But again no injured.
The medical staff had nothing to do, but the rumour that survivors were headed to the area resulted in a steady stream of relatives looking for loved-ones. In the absence of anyone who knew what was going on these desperate people were being directed to a small group of priests and the occasional rabbi. We helped as we could. I remember a man, eyes blurry with tears, language slurred by alcohol. His brother had an office high up in one of the Towers. He knew his brother was gone, he was just seeing if we had a miracle to share, and if we didn't he wanted someone with whom to cry.
I remember a short, partially deaf, septuagenarian woman who couldn't get back to her home, close to Ground Zero. She needed somewhere to go, but you couldn't get through to any of the hostels on the jammed cellphone system. I found her some blankets and a foam mattress and she went to sleep on the floor.
As the night wore on the trickle of refugees and relatives thinned out and most of the volunteers went home with nothing else to do other than watch that same piece of footage looped on CNN. It was becoming clear that there were those who escaped and there were those who died, and in the middle - injured, requiring medical care - there were very few and the vast suite of emergency operating beds was not going to be needed.
I hung around and late in the night another of the chaplains told me he had found a lift down to Ground Zero - we could offer support to the fire-fighters, did I want to go with him? We were driven by ambulance through the road blocks and got off a couple of blocks away.
"Here, take a picture," said my new-found colleague, "I'll use it for the book."
It was round about then that I started to feel uneasy about how 9/11 was going to be used - an uneasiness that has never gone away. I began to speak with the fire-fighters. It was immediately clear how many of these brave men had perished. Company after company had been devastated. I remember one New York fire-fighter who had teamed up with a company from Connecticut, there simply being no one left in his own tight-knit unit of colleagues and friends.
Everyone was waiting for a chance to get "stuck in" and save those they could save, but the fires were too hot and the structures too dangerous. So they sat around in small groups perched on piles of rubble or twisted metal struts. I wandered between them. I can't remember much about those conversations, just sadness and an incredible sense of professionalism. By midday Wednesday I needed sleep - there was a makeshift dormitory a block away but I was ready to head home. I walked out of Ground Zero and a few days later flew back to England to lead Rosh Hashanah services in London.
The day after Yom Kippur I flew back to a transformed New York. As a student I had the same kind of visa as the 9/11 terrorists; immigration had always been a formality. Now, all of a sudden, it became a protracted, almost aggressive affair. I had become a terrorist threat - and I was a white, kippah-wearing Jew. American Muslims I met on an interfaith retreat later that year reported tales of persecution that reminded me more of the darker days of Jewish European history than anything I had known in the supposed land of the free. The crusading discourse of a rattled administration made me feel uneasy and the heavy-handed treatment of suspected "enemy combatants" made me feel ashamed.
I volunteered again, this time with the Red Cross at the newly created Family Assistance Centre. The idea was that anyone affected by the attack could find, in one location, housing assistance, food stamps, employment, counselling and more. Chaplaincy didn't seem to help much. Far more popular than the rabbis were the dogs who would be led round the vast hangar in 40-minute shifts for people to pet and cry over.
By November I was exhausted; sleeping poorly and given to snapping too easily. I went to see the psychologist attached to the seminary where I was studying and poured out three months worth of stories and pain. "What do you want from me?" He asked. I hadn't thought that bit through. 'Permission to stop,' I said eventually.
"It's OK," he said, "you can stop." So I did.