Many workers develop silicosis in their 30s. Some are only in their 20s. Often, there are no symptoms in the early stages. In fact, the disease can develop within a few months of high silica dust exposure or it can go undetected by chest X-ray for 20 or more years of exposure to relatively low levels of silica dust in the workplace. Chronic silicosis may develop or progress even after the cessation of exposure to silica dust. As silica dust builds up in the lungs, it becomes harder to breathe. Silica in the lungs can also weaken the body's ability to fight infections, so other illnesses may result. As silicosis progresses, symptoms may include shortness of breath, severe cough and/or weakness. Fever, weight loss, night sweats, chest pains, respiratory failure and death can also result from silicosis. The National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention estimates that more than one million workers in the United States are at risk of developing silicosis each year. Although the reported number of U.S. deaths with silicosis is about 160 per year, the actual number is thought to be much higher, and hundreds more become disabled because of the disease. In addition, NIOSH reported recently that silicosis deaths continue to occur among workers between the ages of 15 and 44, indicating that intense overexposures to silica dust are still occurring despite the existence of Occupational Safety and Health Administration (OSHA) limits. Although there is no cure for silicosis, it is preventable through effective workplace control measures and elimination of exposure to crystalline silica dust.