At about 2:30, a powerful and pungent odour started to permeate the PhD students room at the College of Computer Science. One rather like that of the solvents used in rubberised fabric. It soon became much, much worse, and the students started leaving. I stayed around finishing off "just one more thing" as the stench became overpowering.
The smell was still pretty awful outside. But nowhere near as bad. I felt a little dizzy, but otherwise had no immediate ill-effects.
Our building is next to the Research School of Chemistry. We still haven't been told exactly what went wrong, whether some equipment broke down, or there was some operator error... we're used to the odd evacuation due to fires or sometimes explosions. But we had no warning, the usual safety alarms weren't sounded telling us to evacuate.
It appears that phosphine, or a compound of phosphine that releases phosphine when exposed to water, was released, and in large quantities. By the time the smell becomes apparent, it's already a toxic dose, and the smell in our room wasn't just bad as it was in the rest of the building, but overpowering.
The odour becomes detectable at 1-3 ppm. The concentration I was exposed to was at least an order of magnitude greater than that, possibly 2. Fortunately only for half an hour: it's the time of exposure that's most important, rather than the concentration. It's not cumulative, and there are no long-term effects unless poisoning is acute.
Symptoms become apparent within 24 hours after exposure. I have a raging headache, but no nausea, no dizziness, and at worst a mildly sore throat and slight cough.
The safety system appears to have completely broken down though, and the RSC still hasn't told us much apart from the fact that Phosphine compounds may have been involved. Usually they go to great lengths to preserve our safety for even the most minor accidents, but now no-one's saying anything.
Phosphine is the common name for phosphorus trihydride (PH3), also known by the IUPAC name phosphane and, occasionally, phosphamine. It is a colorless, flammable gas with a boiling point of −88 °C at standard pressure. Pure phosphine is odourless, but technical grade phosphine has a highly unpleasant odor like garlic or rotting fish, due to the presence of substituted phosphine and diphosphine (P2H4).
Phosphine is highly toxic; it kills at low concentrations.
Inhalation is the major route of phosphine toxicity. Odor is not an adequate indicator of phosphine's presence and may not provide reliable warning of hazardous concentrations. The OSHA PEL of 0.3 ppm is within the range of reported odor thresholds.
* Symptoms of phosphine intoxication are primarily related to the cardiovascular and pulmonary systems and may include restlessness, irritability, drowsiness, tremors, vertigo, diplopia, ataxia, cough, dyspnea, retrosternal discomfort, abdominal pain, and vomiting.
* Phosphine interferes with enzymes and protein synthesis, primarily in the mitochondria of heart and lung cells. As a result, effects may include hypotension, reduction in cardiac output, tachycardia, oliguria, anuria, cyanosis, pulmonary edema, tachypnea, jaundice, hepatosplenomegaly, ileus, seizures, and diminished reflexes.
Toxicity that occurs after inhalation is characterized by chest tightness, cough, and shortness of breath. Severe exposure can cause accumulation of fluid in the lungs, which may have a delayed onset of 72 hours or more after exposure
The symptoms I have are extremely mild, indicating no appreciable danger. At worst, it might give some anomalies in my next blood tests due in about two weeks.
I'll be drinking plenty of water though to ease the strain on my system and help flush it out. And maybe an aspirin or two, the headache is getting a bit worse now, 27 hrs after exposure ceased.