Ok I am not scaring people and I have done my own research. If you read I said to make sure you get food grade DE and to wear a mask. It will cut your hands just like pumce powder and sand if you go rubbing it on things bare handed.
And here is some of the research I have found.
The absorbent qualities of diatomite can result in a significant drying of the hands, if handled without gloves. The saltwater (industrial) form contains a highly crystalline form of silica, resulting in sharp edges. The sharpness of this version of the material makes it dangerous to breathe and a dust mask is recommended when working with it.
The type of hazard posed by inhalation depends on the form of the silica. Crystalline silica poses a serious inhalation hazard because it can cause silicosis. Amorphous silica can cause dusty lungs, but does not carry the same degree of risk as crystalline silica. Food-grade diatomite generally contains very low percentages of crystalline silica. Diatomite produced for pool filters is treated with heat, causing the formerly amorphous silicon dioxide to assume its crystalline form.
In the United States, the crystalline silica content in the dusts is regulated by the Occupational Safety and Health Administration (OSHA), and there are guidelines for the maximum amounts allowable in the product and in the air near the breathing zone of workers.
If you are around flour enough and breath enough in you can get dusty lungs also. So telling people it is completely safe and to go throwing it about in the air without wearing protection is irresponsible and dangerous. Yes you can ingest food grade DE. Bc it is treated.
Flour dust poses a respiratory hazard that can sometimes take up to 30 years to show symptoms in workers. Flour dust also contains allergens that expose workers who weigh or pour flour, or who operate dough mixers. One of the most potent allergens in flour is alpha-amylase, a naturally occurring enzyme in wheat flour that's used to break up large starch molecules and speeds up the activity of yeast.
Asthma is the main risk to workers' health from being exposed to flour dust. Once a worker becomes sensitized to the allergen, even a small amount can trigger an asthma attack with life-threatening symptoms such as wheezing, chest tightness, shortness of breath, difficulty breathing and/or coughing. In British Columbia, the eight-hour occupational exposure limit (OEL) for flour dust is 0.5 milligrams per cubic metre of air. Although the OEL will protect from long-term respiratory disease, it is unlikely that it will prevent occupational asthma as even very low levels to the allergic component can provoke an asthma attack.
So have you warned people with asthma not to use DE? Since you say it is as safe as flour? You my friend need to do your research.