By Robert Walker
Assignment, BBC World Service
Families were left with nothing but what they could carry
Thousands of people were made homeless when Hurricane Katrina struck New Orleans and other parts of the US Gulf coast in 2005.
Many survivors were placed in trailers supplied by the Federal Emergency Management Agency (Fema) - the body charged with dealing with the aftermath of the disaster.
However, many occupants say the trailers were made with toxic substances and made them sick - accusations denied by Fema.
Some trailer occupants, many of whom are still struggling to find adequate accommodation more than three years on, are now suing the agency.
I travelled to Mississippi for BBC World Service's Assignment programme, to hear the story of those left homeless by what some Americans along the coast regarded as their second "Ground Zero".
A home from hell
Paul Stewart and his wife, Melody, moved into their trailer four months after Hurricane Katrina and were among the first to discover what might be causing the problems.
"The very first night we moved in you could immediately sense it in your eyes, nose and throat," he said.
"One morning we woke up and found our pet cockatiel lethargic and unable to hold his balance.
It has been three years and many are still waiting for a home
"We called the vet and he asked us where we were staying," said Mr Stewart.
The vet told them to immediately take the bird out of the trailer as newly manufactured trailers can sometimes have high levels of formaldehyde. The vet thought that might be what is making the bird sick.
"That bird saved our lives, I truly believe that," added Mr Stewart.
Formaldehyde is a substance often used in building materials and furniture, exposure to high levels can cause respiratory problems and even cancer.
Becky Gillette, a volunteer with an environmental group, heard what had happened to the Stewart family.
She thought that because Fema had to procure around 120,000 trailers almost immediately, some may have been made with sub-standard materials - so she raised money to start testing for formaldehyde levels.
"Out of all different kinds of trailers being used, nine out of 10 were very high in formaldehyde.
"If you used the more conservative numbers for long term exposure, 100% were over the limit, we're talking 20 to 40-fold higher than what's safe for people to be exposed to," said Ms Gillette.
"It was so disheartening because Fema kept saying 'just open your windows and everything will be fine', so they continued to deny there was any problem," she added.
The issue was picked up by the media and fear among the trailer occupants across Mississippi began to spread.
Earl Shorty's wife, Desire, was in remission from cancer before she moved into a trailer, and her health had been improving.
However, that soon changed and Mr Shorty, like many others contacted Becky Gillette to obtain a testing kit for formaldehyde. The results showed that they were not living in a safe place.
"I called Fema and I told them what I'd heard and they said 'what do you want us to do?'," said Mr Shorty.
He said he took his wife to hospital and by that time she had started coughing up blood and gasping for breath.
Mr Shorty said his wife died 18 days later.
Doctors told him she had died from a respiratory illness but he believes that it was exposure to formaldehyde that killed her - although there is no proof her death was linked to living in the trailer.
As reports about the formaldehyde levels began to grow, Fema commissioned testing of its trailers, more than a year after the hurricane.
No results were released for a further six months and then in early 2007, Fema concluded that keeping the trailers well ventilated would significantly reduce levels of formaldehyde.
The implication was that if residents left the windows open they would be safe but some former insiders say this was a cover up.
Jesse Fineran worked for Fema and he said the agency knew from late 2005 that formaldehyde levels were dangerously high.
"I would speak to my supervisor on a weekly basis and ask questions about what Fema was doing on the formaldehyde.
"I would ask them about it and was told that is not my job, they knew these people were suffering and they did nothing," he added.
"I no longer work for Fema - at one point when I continued to complain, two guards came into my office, took the computer I had and was told to leave the office and not come back," he added.
Fema declined a request for an interview but has consistently denied any cover-up.
In a statement, the agency said that once it learnt of concerns about formaldehyde it sent staff to investigate complaints and alternative housing was then provided to anyone who requested it.
Under pressure from the US Congress, Fema commissioned more tests, and then earlier this year announced that formaldehyde levels in some trailers were high enough to cause health problems, including an increased risk of cancer.
By this point, two-thirds of those in the trailers had already moved out and Fema began speeding up the process of moving the others into alternative accommodation.
Hundreds of former trailer residents have now taken out lawsuits accusing the government agency of negligence for exposing them to the risks of formaldehyde.
The long-term health effects may not be known for years to come and the legal battle could be a lengthy one.
Many on the coast of Mississippi believe the story of the toxic trailers is just one part a wider failure of government to respond to Katrina.
"I just want the government to admit to their wrongs for what they have done, then I will be at peace, because my wife will be at peace," said Earl Shorty.
Assignment is on air at 0905, 1205, 1605 and 2005 GMT on Thursday 13 November.
You can download a podcast as well at http://www.bbc.co.uk/radio/podcasts/docarchive/