A thief stripping propane tanks of copper lines is putting people at risk, Halifax police warn.

Someone stole the copper lines from two propane tanks outside residences in central Halifax on Monday. In both cases, the highly combustible fuel leaked.

"The person is literally playing with fire," said Const. Jeff Carr, spokesman for Halifax Regional Police.

It was only a few weeks ago when police reported that someone had cut copper from several oil tanks in north-end Dartmouth, resulting in oil spills and expensive cleanups.

"Unfortunately, these crimes seem to be becoming more common, and it's for something as simple as a few dollars worth of scrap metal," Carr said.

For Irving Oldford, $2.10 a pound for good quality copper will pay for a good cup of coffee.

Oldford, who said he picks up discarded pieces of copper from worksites, brought a bag of it to the Bin Doctor in Halifax on Tuesday. He said they take it because he's a regular customer and trust him.

On this visit, he walked away with $16.17.

But knowing what copper is legitimate scrap and what is stolen property can be tricky.

"A few people, they'll come in with shopping carts and they'd have hundreds of pounds worth of copper," said Kevin Caverley, a worker with Canadian Recycling in Dartmouth.

Caverley said it can be a guessing game when it comes to new-looking copper, especially if it has been cut up.

But police said the real problem is a lack of regulation, because metal recyclers are not restricted in what they can buy.

With no new rules in the works, Carr said the problem may continue until the price of copper drops.