Author: Saa Perica, back.ing.agr Sources:
Turns out, a few things could be at play
Fifteen years of study of psychoactive snuffs of South America: 1967-1982--a review
These factors, which can either increase or decrease NNN levels in smokeless tobacco products, include the tobacco type (i.e., dark air-cured tobacco, bright-leaf tobacco, burley tobacco), growing conditions (e.g., geographic region, climate, rainfall), curing techniques (e.g., fire, flue, air, sun), production process (e.g., additives) and storage conditions (e.g., temperature, humidity, duration). With the FDA acknowledging that weather is a significant factor in NNN production, there is no means by which farmers and manufacturers can control the weather in an effort to comply with the proposed one microgram per gram limitation