Dipping tobacco

# Overview
Dipping tobacco (also known as American moist snuff or spit tobacco) is a form of smokeless tobacco.  It is commonly referred to as dip while the act of using it is known as dipping, having a dip, or packing a lip.

# Usage
Dipping tobacco, sometimes called "chew," is commonly confused with chewing tobacco.  Rather than chewing on tobacco, dipping consists of placing a small clump of tobacco between the lower or upper lip and gums. The dip rests on the inside lining of the mouth for approximately 20-30 minutes as saliva carries nicotine to the inferior or superior labial arteries.
While dipping, users often produce excess saliva, which is typically spat out. Swallowing this excess saliva can cause irritation to the oesophagus, nausea, and vomiting, though some long-time users can swallow this saliva with no unusual effects.
Dipping is often seen as a way of experiencing the effects of nicotine without inhaling smoke into one's lungs.

# Cut sizes
The difference between cut sizes are shown in the length of the individual strands of tobacco. 
The common cut types are:
- Dong Cut - Thin strands of tobacco, typically .7 cm long.
- Mid Cut  - Small granules, approximately .1 cm cubed.
- Fine Cut - Very small granules, slightly larger than a grain of sand.
- Pouches - Very finely cut and wrapped in a small envelopes.

## Surface area and absorption
Many smokeless tobacco users have preferences in texture and nicotine absorption rates. The finer cut the tobacco is, the greater its surface area, which correlates with increased nicotine absorption. Additionally, the amount of moisture in dipping tobacco can be affected by cut size, with finer cuts retaining more moisture.

# Health issues

## Cancer dangers
Dipping tobacco has been shown to cause various types of cancer, including oral cancer, esophageal cancer, and pancreatic cancer.  Most researchers emphasize that while smokeless tobacco may be a "less harmful" alternative to smoking, as it causes fewer fatalities, it is not a "safe" alternative to smoking.  
One recent study indicated that smokeless tobacco users are exposed to more NNK, a carcinogen, than cigarette smokers.

## Cardiovascular effects
Studies are inconclusive as to how significantly smokeless tobacco affects users' cardiovascular systems.  One study states that, "Although the evidence is not conclusive, the adverse cardiovascular effects of smokeless tobacco use are less than those caused by smoking but are more than those found in non-users."  Other studies also indicate that smokeless tobacco related cardiovascular risks are lower than that of smoked tobacco.  One study states that smokeless tobacco use has a "modest effect on cardiovascular risk factors in young physically fit men."
However, it is important to note that one Indian study from the state of Rajasthan states, "There is a significantly greater prevalence of multiple cardiovascular risk factors  obesity, resting tachycardia, hypertension, high total and LDL cholesterol, and low HDL cholesterol, and electrocardiographic changes in tobacco users, chewing or smoking, as compared-to tobacco non-users. Chewing tobacco is associated with similar cardiovascular risk as smoking."
Due to contrasting results in studies, many conclude that further research should be done on the cardiovascular risks of smokeless tobacco.

## Addiction potential
Smokeless tobacco contains nicotine, which is its primary addictive agent.
According to European Union policy, Scandinavian or some American smokeless tobaccos are at least 90% less hazardous than cigarette smoking. However, dipping tobacco is still addictive.

## Warning labels
The following three warning labels must be rotated on all tins of smokeless tobacco sold in the US:
- WARNING: This product may cause mouth cancer.
- WARNING: This product may cause gum disease and tooth loss.
- WARNING: This product is not a safe alternative to smoking.

# Smokeless tobacco companies
Connecticut-based UST Inc. held 62.5 percent of the market as of the third quarter of 2006, according to Morningstar investment research firm. The company's brands include Copenhagen, Skoal, Husky, and Red Seal. The next two largest entities are the Conwood subsidiary of Reynolds American Inc., and Swedish Match. In 2006, smokeless and "spit-less" tobacco products were test-marketed by Altria Group Inc. (formerly Phillip Morris Companies) and R.J. Reynolds Tobacco Company, the former named Taboka and the latter under the brand name Camel Snus.