Fifteen percent of adult asthmatics can trace the beginnings of their asthma back to their jobs, according to a report on About.com. Occupational asthma is the most common of the occupationally acquired respiratory diseases. It's estimated that there are more than one million Americans with occupational asthma.

Overall, there will be more than 65,000 adult Americans with new cases of lung disease related to their jobs this year, says the report. This year 25,000 people will die as a result of occupationally acquired lung disease. Occupational Lung Disease is the number one cause of work-related illness in the U.S.

The two basic types of occupational lung disease are those caused by inhalation of various types of dust and those caused by a hypersensitivity to substances encountered at the workplace. Combinations of these two types and certain lung cancers are also triggered by workplace exposures.

Here's a list of some of the major occupational lung diseases and their causes:

Asbestosis — caused by exposure to asbestos dust.

Berylliosis — caused from inhaling the dust or fumes containing beryllium, used to make fluorescent bulbs and in the aerospace industry.

Byssinosis (Brown lung) — effects the small airways causing chronic obstruction; caused by inhalation of dust from hemp, flax or cotton and prevalent among textile workers.

Coal Worker's Pneumoconiosis (CWP) (Black lung) — found exclusively in those that work with and around coal.

Silicosis — the oldest known occupational lung disease; caused by inhaling silica dust, typically generated in foundry work, pottery, glass making, and ceramics such as tiles and bricks.

While most occupationally acquired lung diseases are not curable, they're all preventable, says the report.