HOUGHTON - In April, some letters which contained the poison ricin were sent to a United States senator and the White House, but no one was hurt by the toxin, which can produce devastating health effects.
Another suspicious letter was received in April at the Saginaw office of Sen Carl Levin, D-Detroit, but tests for ricin and other toxic substances were negative.
Although the person or persons who sent the ricin-laden letters may have had terror intentions, two members of the chemistry department at Michigan Technological University said although it can be deadly, the substance is not very effective for such a purpose.
Tarun Dam, associate professor of chemistry at Tech, said ricin is derived from the castor bean. It is a protein of the bean and it acts as a defensive mechanism for the plant.
"They don't have an immune system like we do," he said.
However, Dam said the protein is very efficient at destroying the cells of other organisms. It's that function which makes ricin attractive to researchers.
"It's a very interesting protein from a scientific point of view," he said. "What fascinates us is its mechanism."
Some researchers are using ricin in cancer studies because it can be so easily directed at certain cells, Dam said.
"It's like a guided missile," he said.
Sarah Green, chair of the Tech chemistry department, said ricin stops all cell activities of the organism it attacks. However, ricin is effective as a weapon against humans only under certain circumstances.
"If you inject it, that's when it's most toxic," she said.
In order for ricin to be effective as an airborne substance, Green said it would have to be a very fine powder and a huge quantity, perhaps tons, would be needed to make it a weapon of mass destruction.
A person who breathes or ingests ricin powder would get sick, but as long as an infected person received medical attention, that person would probably not die.
"Most people get sick, but they will survive," she said.
"You'd have to make industrial (quantities)," Dam said.
However, if untreated Green said ricin poisoning can produce serious health problems, including effects on the skin, organs, stomach and intestines, among many others. It can be fatal, also.
Despite its possible toxicity, Green said only someone with a training in chemistry could make ricin an effective weapon.
"It takes quite a bit of purification," she said.
Because so much ricin in a very specific form would be needed to do significant damage, Green and Dam said most terrorists wouldn't use it.
"It's not a very good terrorist weapon at all," Green said.