In June 2018, OSHA introduced the silica standard so workers exposed to silica-generating tasks would be protected from the hazards of silica and silica dust. Just over a year in, we have seen some companies still failing to comply, others still in the process, and others doing quite well.
Breathing in very small "respirable" crystalline silica particles causes multiple diseases, including silicosis, an incurable lung disease that leads to disability and death. Respirable crystalline silica also causes lung cancer, chronic obstructive pulmonary disease (COPD), and kidney disease. Silica dust is harmful when inhaled into your lungs -- it is 100 times smaller than a grain of sand; you can easily be breathing it in without knowing.