Texas Tech University

Failure to Properly Clean Equipment Allows for Buildup of Energetic Materials Leading to Detonation

What Happened?

On January 1, 2018 in a Mechanical Engineering Research lab a graduate student researcher was injured when a detonation occurred while grinding aluminum and iodine oxide powders. The student received a minor chemical burn on the hand and was taken to the hospital immediately after the incident. The student was following established procedures while trying to create 2 grams of material for XRD analysis. Procedures required limiting the total material of powder to 10-20 milligrams and grinding multiple small 'batches' to develop enough material for analysis.

All students and personnel involved were wearing appropriate personal protective equipment including lab coats, safety goggles and gloves.

Area in protective reaction chamber where grinding and detonation took place.

Area in protective reaction chamber where grinding and detonation took place.

close up of chemical burn on hand

Chemical burn and injury to hand of student.

What was the cause?

The root cause was determined to be the buildup of material on the pestle over multiple batch preparations. After the student ground the 10-20mg of material in the mortar and pestle they would collect the ground material that was in the mortar but not thoroughly clean pestle. It is predicted that over the multiple batches prepared material built up on the pestle until there was enough to allow a detonation.

  • Buildup of aluminum and iodine oxide powders over multiple grinding events due to pestle not being cleaned between batches.

What corrective actions were taken?

Environmental Health and Safety (EH&S) staff investigated and released the lab the following day. The investigation included a recommendation which is provided below:

  1. Procedures for multiple batch preparations of energetics must include thorough cleaning of all equipment between batches when buildup of these materials can occur. Laboratory Standard Operating Procedures in all energetic labs must be amended to include this step.

How can we prevent incidents like this?

Review written procedures to make sure that they reflect the risk of buildup of energetic materials on equipment.

Resources

Section A10.13 of the Texas Tech Laboratory Safety Manual

Environmental Health & Safety