Related is the danger of smoke from ordinary wood fire, see: http://www.samharris.org/blog/item/the-fireplace-delusion

I don't think you can say that at all. Of course burning plant matter produces carcinogens, but studies of marijuana smokers haven't found any conclusive evidence of greatly increased cancer risk. There have been some studies that show that smoking tobacco and marijuana together increases cancer risk beyond that of tobacco alone.

Smokeless tobacco causes mouth and throat cancers, so something is going on with tobacco itself (or something else common to cigarettes and smokeless tobacco).

There is some evidence that radioactive carcinogens found in tobacco play a part in cancer risk.

There is epidemiological evidence that marijuana smoking is associated with lung cancer. "Greatly" is subjective so I can't really comment on that.

"findings from a limited number of well-designed epidemiological studies do not suggest an increased risk for the development of either lung or upper airway cancer from light or moderate use, although evidence is mixed concerning possible carcinogenic risks of heavy, long-term use,"

"In summary, the accumulated weight of evidence implies far lower risks for pulmonary complications of even regular heavy use of marijuana compared to the grave pulmonary consequences of tobacco."

By greatly, I meant as bad as tobacco which dramatically increases the risk of lung cancer.

The previous poster was commenting on the health risks of tobacco being caused entirely by burning plant matter. However, the evidence suggests this isn't true.

> "In summary, the accumulated weight of evidence implies far lower risks for pulmonary complications of even regular heavy use of marijuana compared to the grave pulmonary consequences of tobacco."

Yeah, I think mostly this comes down to the above discussion of "greatly" -- marijuana seems to have some correlation with lung disease and cancer, but it seems to be less than tobacco.

http://www.cdc.gov/tobacco/data_statistics/fact_sheets/tobac...

would be the volume of smoke inhaled (hookah session = 150 cigarettes). Equivalent is probably the wrong word to describe that.

OT: "Hookah is also called [...] hubble-bubble [...]"

Citation needed.

There are multiple uses of it in Google search results.

"Other common names for waterpipes include [...], and hubbly-bubbly."

They even cite a study entitled "Hubble-bubble (water pipe) smoking: levels of nicotine and cotinine in plasma, saliva and urine". [2]

This rabbit hole goes deep!

[1] http://www.lungusa2.org/embargo/slati/Trendalert_Waterpipes....

[2] Shafagoj YA, Mohammed FI, Hadidi.KA., Int J of Clin Pharmacol Ther 2002 Jun; 40(6): 249-55.

This known carcinogen should be treated with respect, even when taken by alternative routes, until there is data demonstrating that the cooling mechanism actually improves safety.

My main intent was to save every other person that did a double take the trouble.

Knowledge is potentially unbounded, but I wouldn't say we "lack" anything. Marijuana is probably the single most well-studied substance on the planet. Most FDA-approved drugs have gone through only a fraction of the level of study and testing that marijuana has.

> The experts with whom I have discussed this (a few pulmonologists) usually ask about marijuana smoke in the same breath as tobacco smoke, and consider it a probable carcinogen.

I've done a lot of research on this topic; unfortunately it's on another hard drive at the moment, but thankfully it's a very easy topic to research yourself.

Marijuana itself is not carcinogenic - in fact, it has cancer-fighting properties in some cases, and could be used as an aid in treating cancer directly, not just symptomatically. Consuming marijuana in edible or vapor form possesses no risk of cancer.

Interestingly, there have been a number of studies on heavy marijuana users (who smoke marijuana), and by and large, they have failed to conclude that even moderately heavy use of (smoked) marijuana can be linked to lung cancer. This phenomenon is well-known enough that it has spawned its own set of associated explanatory theories, and studies investigating those.

Obligatory XKCD disclaimer: https://xkcd.com/882/

I would like to see a citation of a study that is powered to detect population-level effects which demonstrates that claim.

As an aside, I'd also like to see solid data on vapor form tobacco. There is not a definitive study at this point to demonstrate safety or clearly delineate the risk. It would be nice the be able to give meaningful guidance to patients on the topic of marijuana and tobacco, but right now I believe the most accurate and responsible thing to say is "I don't know."

Regarding pot not causing lung cancer I can't really argue, emphasima on the other hand is a very real thing. While this is anecdotal, my mother is a nurse in a country town where there are a lot of weed only life long smokers and most of the old boys are starting to show up in hospital with emphasima.

My understanding was that there is about 10 cigarettes worth of tar in a similarly sized joint.

I have heard the old wives story about weed doesn't cause cancer many times. Never have I found any study pertaining to it. Or have I been shown any proof. The idea that there is no carcinogens created from burning plant material of any kind is laughable to me. The amount is questionable only maybe.

As from personal experience, heavy daily usage is certainly detrimental to health and breathing capacity.

There is a lot of misinformation out there take my views and others with a grain of salt.

Disclosure, ive always been a staunch legalisation supporter. Never been a fan of decriminalization.

Edit, and no I dont smoke anymore.

That may be true, but how much does your average pot smoker actually smoke in a day? My dad was a two-pack-a-day cigarette smoker, which is forty cigarettes. I have yet to run into someone who smokes four cigarettes worth of pot in a day, and while I'm sure they must exist from what I can see the average is more like an amount similar to the tobacco you'd find in a quarter of a cigarette.

4-5 a night is very common, at least where I've come from. I'd say about as common as someone who drinks 4 beers in a night after work. Not the total norm but not crazy or anything either.