Waste explosion at Texas Tech

On Feb. 2, a glass waste bottle exploded in a Texas Tech University teaching laboratory, injuring three undergraduate students and a graduate teaching assistant. TTU has nowposted its investigation results online.

In short, a nitric acid wash step was eliminated from the lab but the written instructions were not revised (I don’t know how this was communicated–with a verbal “skip step X”?). Nitric acid waste then wound up in a bottle with methanol and dimethylglyoxime, reactions ensued, pressure built up, and the bottle exploded when a student later tried to open it.

The good: “All students and personnel were wearing appropriate personal protective equipment including lab coats, safety goggles and gloves.”

The bad: The waste bottle was labeled with HNO3, HCl, methanol, and dimethylglyoxime. Clearly the lesson is not getting through to people that you can’t mix nitric acid with organics. Also, people need to keep written procedures up to date. It’s not hard to see how a verbal instruction would get ignored in favor of what’s written down, not to mention what happens if the person who historically runs the lab is out sick or has left the department.

TTU is surely not the only institution challenged by these things. I would also argue that TTU should be commended for continuing to make its incident information available so that others in the academic and chemistry communities can learn from the experience.

TTU’s action items to move forward:

1. EH&S will be providing pressure relief caps to waste storage bottles that contain inorganic acid wastes.
2. Faculty, instructors and TA’s should communicate unique safety concerns at the beginning of teaching labs prior to any experiments. The safety concerns should reflect the hazards posed by that experiment.
3. Responsible individuals over teaching labs should revise their teaching procedures regularly and review for possible hazards that can be eliminated. Any additions or deletions should be reflected in handouts provided.

If people could use nitric acid + organic solvent visual for training purposes, this YouTube video seems useful:

Author: Jyllian Kemsley

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  1. Missing from the evaluation of the incident is also the incorrect labeling of the waste container and failure to follow proper waste segregation requirements.

    TTU’s Chemical Hygiene Plan: “Each individual chemical waste added to container – This must be the full name, abbreviations or formulas are not allowed;” “Inorganic acids and organic waste shall be stored in separate cabinets or areas.”

    It would also be good for TTU to update their CHP’s Chemical Segregation section (Appendix A) to include language which states the same requirements for segregating stock materials must also be applied to chemical wastes.

    I would also imagine that your conclusion “Clearly the lesson is not getting through to people that you can’t mix nitric acid with organics” may not be particularly accurate or fair. Were these people trained on segregation? Were they trained on proper waste management and labeling? There is a CHP, but what process has TTU followed to ensure these people are familiar with it and have adequate knowledge of its contents? Unless you have more information from the investigation than is present in your article or the post on TTU’s website, it would appear you are jumping to a conclusion that is not inherently accurate, nor helpful.

  2. The other consideration here is that mixed waste can result in mixtures with different properties. For example, the mixture of HNO3 and HCl is known as Aqua Regia and is a very strong oxidizer that will not only react with organics, but is also used to dissolve various metals. In general, mixing inorganic acids and oxidizers will result with an oxidizing mixture that is much more reactive than without the acid (e.g. Piranha solution — H2O2/H2SO4).