According to Department of State Health Services records, more than 110 facilities across the state store ammonium nitrate in some form. Some companies hold it in powder form, like the depot in West, which in 2012 reported storing 540,000 pounds of the chemical. Others store it in a liquid solution, which is a much less volatile form, said Charles Mitchell, a professor of soil sciences at Auburn University.

Investigators have said that ammonium nitrate was the source of the explosion at a fertilizer depot that killed at least 14 people and injured hundreds more last month in West. Questions have been raised about why such a volatile substance was stored so close to West Independent School District buildings, three of which — including the entire middle school — will need to be demolished in the wake of the West explosion. Using data collected in the creation of the Tribune's Public Schools Explorer, and state hospital location data from the Department of State Health Services, we have mapped each facility that stores ammonium nitrate and the five closest schools and hospitals to it. Use the dropdown menu below to view each facility on the map.

Editor's note: This data should not be construed to suggest that the facilities represented pose a danger. This interactive shows where the chemicals are located, how much of each chemical is stored and the facility's location in relation to schools and hospitals in the area.