THE BANG ISN'T THE ONLY RISK OF HIGH EXPLOSIVES

It's common to think that the "bang is the biggest risk of high explosives. However, there are serious health and environmental risks associated with explosives and explosive residue that workers must be aware of.

A good example is nitroglycerin. Although it's the basis of dynamite and other high explosives, it is also a powerful medicine for people with heart conditions. Nitroglycerin affects the cardiovascular system, blood, and nervous system of humans. It opens the blood vessels which is important for someone suffering from some heart problems. However, acute exposure to nitroglycerin can cause headaches, nausea, vomiting, occasionally diarrhea, sweating, and lightheadedness. High exposure can cause abdominal cramps, vomiting, mental confusion, convulsions, breathing difficulties, or death. Chronic exposure to nitroglycerin can lead to the development of tolerance, and sudden withdrawal from exposure can result in angina-like chest pains.

But nitroglycerin isn't the only hazardous explosive. TNT has been associated with liver and blood damage, anorexia, and anemia. RDX and HMX have been associated with systemic poisoning usually affecting bone marrow and the liver.

Nor are the risks limited to military type explosives. Ammonium Nitrate, the key ingredient for ANFO, which is common in mining can cause a decrease in blood pressure; roaring sound in the ears with headache and associated vertigo; nausea and vomiting; collapse and coma. That doesn't include the hazards of the detonator compounds, which often contain heavy metals.

The hazards don't disappear after the explosive is used at a mine. The detonated explosive releases toxic gases, primarily oxides of nitrogen and carbon monoxide. Nitric oxide (NO) and nitrogen dioxide (NO2) are produced by large surface blasts in which the explosive does not detonate properly. NO released by the detonation oxidizes to NO2 as the fumes mix with the atmosphere. Excessive NO2 production is apparent as an orange cloud that forms above the blasting site. NO2 is extremely toxic.

Not all toxic gasses are dispersed with the wind. A lot of NO and NO2 gasses are trapped in the muck pile for hours. Miners must be aware that additional NO and NO2 gasses will be released during the mucking that could be hazardous even hours after the blast. Since NO oxidizes into the more deadly NO2, concentrations of this nitrogen dioxide remain deadly for a longer period of time.

Carbon monoxide (CO) is also released by the detonation of explosives. CO is not a problem after large surface blasts because it quickly dissipates in the atmosphere to safe levels. CO dangers are more of a problem for construction, trench, and underground blasting. If a mine worker walks onto a blast site too soon after a blast, the CO emanating from the muck pile poses a serious risk to the worker. CO may also migrate hundreds of feet through the ground to collect in a homeowner's basement, manholes, and other confined spaces. Between 1994 and 2005, eight miners were injured by exposure to blasting fumes.

There is a push to develop "green explosives" that can reduce the environmental and health danger of traditional explosives. One area of study is in developing lead free primary explosives, which are used to detonate the main charge. These lead compounds are also frequently found in commercial ammunition primers. They have developed primary explosives based on a chemical called nitrotetrazole that may replace them. Other chemists are also looking at organic explosives produced by genetically engineered bacteria.

Explosives also pose a long term hazard if they contaminate the soil. Although the traditional method of removing the dirt to a toxic waste dump is still acceptable, there are other ways to eliminate the contamination during reclamation. There are some plants that can absorb chemicals like high explosives from the ground and chemically break them down or "exhale" them. In this method, plants pick up the contaminants through their root system and then with the help of enzymes break it down into simple molecules that can be incorporated into the plant tissue. This method was used by the Army to clean up a site contaminated with TNT.