Although the health risks of exposure to asbestos were known and documented as early as the 1930's it wasn't until the 1960's that the asbestos warnings became commonplace and both the public as well as manufacturers started to decrease their use of the material. Early research was inclusive as to what asbestos level may be considered safe, largely due to the lengthy lag time between exposure and the development of the most significant of the symptoms. In many cases exposure and diagnosis still has up to a 50 year lag even though the actual individual may have the general symptoms of asbestos exposure that have been affecting their health for years. Typical symptoms include breathing problems, weight loss, lack of energy, chest pains, coughing and chronic respiratory infections or colds. Modern research has shown that both amount as well as duration of exposure can influence the asbestos level that individuals can tolerate without developing any health conditions. Issues with the type of asbestos fibers as well as the actual dimensions of the airborne fibers can also affect the levels.