WHO, WHAT, WHY?
The Magazine answers...
Hair and fur stuffed into tights are the latest tool in the Deepwater Horizon clean-up. The hairy booms won't plug leaks on the seabed, but will be floated off beaches to mop up oil washing towards shore. Why?
Making one of the oil spill hair booms
How's your hair - shower-fresh, or a bit greasy around the roots? We wash our hair because it collects the oils our bodies produce.
And it's this property of hair - and fur and wool - that means it will be used to help tackling the oil spewing from BP's ruptured well in the Gulf of Mexico. It's adsorbent rather than absorbent, meaning oil clings to the many tiny scales on each strand of hair.
"Each follicle [strand] of hair has an enormous amount of surface area. It's not soaking up the oil, it's not blowing up like a sponge - the oil is coating the outside," says Lisa Gautier, founder of the ecological charity Matter of Trust, which runs an international Hair for Oil Spills programme to collect off-cuts from hair salons and pet groomers, sheep farmers and individuals.
The donated hair and fur is then stuffed into nylon tights to make sausage-shaped booms to string out along beaches, as officials have said there are not enough manufactured booms to protect the coastline from the looming oil slick.
"Hair is an extremely efficient material for taking in all kinds of oils including petroleum - it clings to the hair because it's spiky," says Ms Gautier.
The technique has been tested and approved by the United States Environmental Protection Agency. It was used in past disasters, such as 2007's Cosco Busan oil spill in San Francisco Bay and in the Philippines in 2006, when prisoners shaved their heads and chests to donate hair to the clean-up effort.
And in the first Iraq war in 1991, when retreating Iraqi soldiers released million tonnes of oil into the Persian Gulf, New Zealand sent booms filled with sheep's wool that could soak up 40 times their weight in oil to help with the clean-up.
At the time, Malcolm Fox, a chemist and visiting professor at Leeds University, studied the use of low-grade wool in oil spill clean-ups.
"An oil company sent me a drum of the crude oil/water emulsion and we tried soaking it up with mats of the wool. It was reasonably successful and we recycled the wool mats by putting them through an old washing mangle to recover the oil, which could also be used again."
Human hair, however, proved more effective - in part because the wool had been processed and so lost its lanolin coating, which naturally repels water and holds grease to keep sheep warm.
"Human hair grease acts as a spreading agent, to help the oil form a film on the surface."
The idea of using human hair to mop up oil spills dates from the Exxon Valdez accident in 1989. Watching the unfolding disaster on television, Alabama hair stylist Phil McCory noticed how hard it was for volunteers to clean oil from otters' fur, and thought to himself: "If animal fur can trap and hold spilled oil, why can't human hair?"
Prisoners in Manila bagged up their hair for a 2006 oil spill
So he staged a home oil spill to test this theory, pouring a gallon of used motor oil into his son's paddling pool. He then dunked in a pair of his wife's pantyhose stuffed with clippings from his salon. Within two minutes, the DIY boom had sucked up all the oil.
He then parlayed this brainwave into a business making oil spill mats from hair purchased in China. For the past 10 years, his company has worked with the Matter of Trust charity to establish a hair recycling system to find a use for the all the hair and fur cut off by stylists and pet groomers each day. The charity's figures suggest this amounts to 370,000 pounds of hair, and 300,000 pounds of fur, a day in the US alone.
While fur, horse hair and feathers are also used in the booms, the charity says human hair seems to be most effective as it has less natural oil and so more capacity to catch spilled oil.
WHO, WHAT, WHY?
A regular part of the BBC News Magazine, Who, What, Why? aims to answer some of the questions behind the headlines
To make a hair boom, first cut the legs off a pair of tights, and fit the open end over a wide plastic pipe - this makes it easier to feed the hair and fur into the stocking. Once it's full, tie off the end and cover the resulting sausage in a strong mesh.
While the charity welcomes all donations, there are a few caveats - it prefers freshly-washed hair and fur, and hair to be from the head only. This is because each boom is hand-made, and its volunteers are unlikely to want to handle filthy - or intimate - off-cuts.
But what happens to all the oil-soaked hair? Among the options tried by the charity include feeding the whole mess to worms to break down into fertiliser.