Question: "We discovered a few months ago that a house in our neighbourhood had a grow-op. It came as a surprise because the house looked nice, and it wasn't run down. We saw people living there. What signs or smells should people be aware of or suspicious of if they suspect a grow-op is in the vicinity? There has been talk of legalizing marijuana. Should ordinary citizens still be proactive in informing the police? Are citizens allowed to remain anonymous?"

Marijuana grow operations (or grow-ops) can range from a few plants growing in a person's home to thousands of plants grown in a warehouse or in remote outdoor locations. Whenever a grow-op gets taken down by police, it generates a lot of media and public interest. Recently, a reader of The NOW who wished to remain anonymous asked how to recognize if there is a grow-op nearby and whether it should be reported.

I know the politics of pot is everywhere right now. Issues of legalization and decriminalization and licensing of marijuana for medical use are debated all the time. But this column focuses on policing not politics, so I'll stick to the facts.

First fact: it is currently illegal to possess or cultivate marijuana unless you have a licence and are abiding by its terms.

Second fact: Marijuana is the most heavily consumed illegal drug in Canada and the level of THC (delta-9-tetrahydrocannabinol, the psychoactive ingredient in pot) in today's plants is more than twice what it was 10 years ago.

Third fact: Cultivation of marijuana plants often involves toxic chemicals and can carry other very serious risk factors such as:

. Electrocution and fire: Grow operations use an extraordinary amount of electricity, and unlicenced growers will often tamper with wiring and bypasses to get the most power for the lowest cost, even to the extent of stealing power from neighbouring residences or businesses. The tampering drastically increases the risk of electrocution, power outages and electrical fires, all of which can pose a serious risk to people or property in the vicinity of the grow op.

Air quality: Pot plants like warm, damp environments so growers will also tamper with venting systems for the good of their crop. This creates a perfect environment for moulds and fungi that can be toxic even if the grow-op itself has been dismantled. Moulds and fungi are also an added risk in the case of electrical fires.

Dangerous chemicals: To grow the largest possible crop in the least possible time, growers will often use a variety of chemicals and fertilizers. The fumes from these substances can be dangerous, as can the chemical reactions caused by improper mixing and disposal. This poses risk to the natural environment as well as air quality in the grow-op and the surrounding area.

Violence: This is one of the areas that concerns the police the most. The occupants of a grow-op are more susceptible to violent extortion or home invasion involving guns and machetes as criminals attempt to settle scores and steal crops for profit. The big risk here is that pot thieves may not be aware that the grow-op has been dismantled and the grower has moved on or pot thieves could just get the address wrong and break into an innocent person's home or business by mistake.

Fourth fact: Grow-ops are a threat to the safety of your neighbourhood so if you suspect there is one in your vicinity you should absolutely report it to police. We work with partners in the federal government to determine whether reported grow-ops are licenced and proceed accordingly.

How do you spot a grow-op in your neighbourhood? Here are some of the common clues that a property is being used to grow marijuana.

. The building is a rental that is used or visited infrequently. Rental buildings (including warehouses) are often used by growers to avoid damage to their own property. Also, growers are usually on premises occasionally and for a short period of time.

. You can see signs of heat and moisture like condensation build up on windows due to high humidity levels inside. And on cold winter days, you may notice the roof of a grow house lacks snow or frost because of the high temperature marijuana plants require.

. You can smell a "skunk-like" odour outside, especially when the inside air is being vented out, despite the use of filters.

. Industrial garbage like plastic piping, wiring and fertilizer containers.

. Electrical equipment inside creates excessive humming sounds.

The most important thing to note is that you should never put yourself at risk to gather evidence. Just follow the golden rule of public safety: if you SEE something, SAY something. I think it's in the best interest of the neighbourhood to report them to the police if you suspected there is one near you.

. "Cop Talk" is a monthly column produced as a partnership between the Coquitlam RCMP and the Coquitlam NOW based on questions submitted by readers. Cpl. Jamie Chung is the media relations officer for the Coquitlam RCMP. Questions can be submitted to editorial@thenownews.com. You can follow Cpl. Chung on Twitter (@rcmpjchung) and visit the Coquitlam RCMP's website (www.coquitlam.rcmp.ca) for more information about policing and public safety in your community. The contents of this column are based on Cpl. Chung's professional opinion, training and experience and are not intended to reflect official RCMP policy or other legislation.