Environment Canada enforcement officers launched hundreds of investigations, typed up thousands of warnings and carried out tens of thousands of inspections over a recent seven-year stretch.
But over that period they nailed down only 32 convictions - putting the annual average at less than five.
The department's work led to a pair of recent convictions, which is more than they achieved in some entire years.
Enforcement personnel pursue environmental violations in everything from shipping containers destined for Asia to local dry-cleaning operations, which commonly use a toxic solvent.
But the director of Environment Canada's enforcement branch says convictions aren't always the goal, and that even written warnings can be effective deterrents.
"People think that enforcement ends up in prosecution and that's not necessarily the case for us," Manon Bombardier said in an interview.
"Prosecution is one of the tools, but it's not the only one at our disposal.
"The numbers can be misleading."
Bombardier noted that officers have several enforcement measures at their fingertips. The course of action is determined by the severity of the violation as well as the offender's track record.
But prosecution remains an important tool.
The recent convictions highlight how officials nabbed two businesses that tried to illegally transport toxic electronic waste - or e-waste - out of the country.
One company was fined $10,000 for exporting old computer and electronic parts to China, while another business was hit with $30,000 in penalties for attempting to ship 1,200 used lead acid batteries and seven monitors abroad.
A former chief of Environment Canada's enforcement branch argues the department should be prosecuting even more.
"There's no point in having strong federal environmental laws unless you're going to enforce them, which has not been the case in Canada," said New Democrat MP Linda Duncan, an environmental lawyer who headed the enforcement office in 1988 when it employed only a handful of people.
"It's not good enough just to monitor."
Between 2002-03 and 2008-09 - the most recent Environment Canada statistics available on its website - officers performed close to 35,000 inspections and handed out nearly 9,000 warnings.
Over that period, the department also launched 288 investigations, leading to just 32 convictions under the 1999 Canadian Environmental Protection Act.
The Conservative government pledged to get tough on environmental offenders in 2009 when it passed legislation providing for stiffer penalties. But increased fines that are part of the law have not yet come into effect.
In recent years, the department has also allocated more than $40-million to improve the enforcement branch's forensic capabilities and beef up the force to 320 officers.
But Ms. Duncan insists the government needs more policing of polluting industries, particularly when it comes to the oil sands.
"The mentality that's developed in Environment Canada is [that]we've gone back to the '60s, where the department is the friend of the industry," the Edmonton MP said.
"A lot of us worked very hard to get rid of that mentality to remind the government that they actually were the regulator."
Ms. Duncan said it often takes private prosecutions to spur the federal government to "step up to the plate."
She noted that last year's conviction of Syncrude Canada was kicked off by a private prosecution.
Syncrude was ordered to pay $3-million in federal and provincial penalties for causing the deaths of 1,600 ducks in its oil sands tailings pond.
Ms. Duncan applauded the federal government for joining in on the prosecution - now it's time, she says, to deploy more officers and intensify inspections at oil sands installations.
"It defies logic that there isn't a big coterie of officers there full time," she said.
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