There's bad news for Canadians selling elephant tusks illegally – thanks to science, you can no longer pretend ivory is antique and get away with it.

Authorities can now use radiocarbon dating to determine exactly what year an elephant was killed, showing whether its tusks were legally obtained or not.

Under international regulations, tusks can only be legally sold if:

The elephant they belonged to was taken from the wild before July 3, 1975.

The seller can prove they were legally imported into Canada.

Environment Canada used the new technique for the first time to convict Toronto-based Five Star Auctions and Appraisals, and company director Chun Al Jin, in February, the department said in a news release this week.

The company and Jin were each hit with a penalty of $9,375, or a total of $18,750, and had to hand over two tusks to authorities.

The company had claimed that the tusks were antiques.

But a radiocarbon analysis of the tusks showed that they likely both belonged to the same elephant, killed in 1978 plus or minus a year, said Guillaume Labrecque, of the radiochronology laboratory at Quebec's Laval University, who helped conduct the analysis.

"You can't really argue with this," he said. "The facts are right there."

Radiocarbon dating is a technique commonly used in forensics and archeology to figure out the age of materials that come from plants or animals, such as bone or wood. It's based on the fact that one form of carbon – carbon-14 – is radioactive and decays over time. Living things are constantly adding new carbon-14 to their bodies, but once they die, the amount of carbon-14 in their tissues declines at a known rate compared to the amount of non-radioactive carbon. That allows their time of death to be extrapolated.

Labrecque said radiocarbon dating of samples from before 1950 generally give dates within 15 to 25 years.

But younger samples contain higher concentrations of carbon-14 because extra carbon-14 was added to the atmosphere by nuclear tests in the 1950s. That allows more precise measurements.

The idea of analyzing elephant tusks with radiocarbon dating to identify illegal specimens was developed by Kevin Uno, a postdoctoral researcher at Columbia University in New York, who published a paper about it in 2013.

A magazine article about the process was spotted by Todd Kish, a field officer at Environment Canada, who contacted Uno after seizing some suspicious elephant tusks, Uno recalled.

"I said, let's try it. It sounds awesome."

Cross-border issues

They hit a snag because international laws to prevent the trafficking of endangered species made it illegal to send the tusks to the U.S. for analysis. So Uno asked Labrecque to use a chemical procedure to convert the material in the tusks to pure carbon dioxide.

"You can ship CO2 gas anywhere in the world," he said.

Labrecque and Uno also collaborated with the University of California, Irvine on the analysis, which costs about $1,000 US per tusk.

Uno said this is the first time the technique was used in a true forensics case.

"This is the first application that's gone to court and was instrumental in the guilty plea that was entered."

He now hopes to use it in other countries.

A study last year found poachers killed an estimated 100,000 elephants across Africa between 2010 and 2012, a huge spike in the continent's death rate of the world's largest land mammals. The slaughter was blamed on increased demand for ivory in China and other Asian nations.