Allotropes of phosphorus: properties, hazards, and fire suppression methods

Phosphorus Handling and Safety Advisories

There are many tricky chemical substances out there in the world that must be handled with the appropriate care and caution. Phosphorus is one of those chemicals. White phosphorus is extremely toxic, and as such must be handled with gloves; while it is also important for firefighters to remember to use dry sand when extinguishing a red phosphorus fire.

There are several different types of phosphorus that have differing toxicity levels. For example, red phosphorus is relatively harmless, with extremely high levels of contact needed to impose a danger to the handler. However, unlike red phosphorus, white phosphorus is much more dangerous upon contact. Here, the research suggests that "this allotrope of phosphorus is extremely toxic and the estimated human lethal dose is 50-100 mg" (Princeton University, 2011). This is much more toxic than red phosphorus. As such, it is important for those handling white phosphorus to take the necessary precautions so that they avoid exposure to higher levels of dangerous toxins. Princeton University advises that "when working with amorphous phosphorus, it is prudent to consider the potential for yellow phosphorus contamination and related precautions required to handle the material safely" (Princeton University, 2011). This means often wearing safety glasses, fire retardant lab coats, and most importantly "impervious gloves" (Princeton University, 2011). With such high toxic levels in the substance, handling the material without the proper safety precautions could be a danger and cause toxic poisoning. This shows why it is crucial to wear gloves while handling the much more toxic white phosphorus.

In addition, it is also crucial for firefighters to remember to use dry sand when extinguishing a red phosphorus fire, rather than using the typically used wet sand to extinguish other types of fires. Red phosphorus fires are considered a hazardous fire, due to the chemicals that are burning inside of them. In such events, it is suggested for fire-fighters to use dry sand or dry powder to extinguish such fires (FM 5-145). There are still high levels of oxygen in water, or H2O. As such, wet sand only continues to feed the flames, rather than take the necessary oxygen out of the fire in order to properly distinguish it. There is simply too much oxygen in wet sand, making it a danger for the fire to not go out, or even worse, to increase its ferocity. Therefore, dry sand is a much better option, because there is much less oxygen within its contents. Rather, this lack of oxygen strangles the fire's life source and helps extinguish it. Dry sand or dry powder is often recommended for extinguishing chemical fires of various types, along with red phosphorus flames. Fires burning with hexachlorethane (HC) also require the use of dry materials like dry sand. Dry sand can be augmented with the use of other chemicals as well, such as magnesium, only in some specific cases.