What happened? While a lab worker was restocking a flammable storage cabinet with reagents, a shelf full of chemical bottles collapsed. Four, 4-liter bottles of chloroform, a liter bottle of dimethylformamide and a 100 ml bottle propionic acid fell and broke. The lab worker slipped and fell while trying to catch the falling bottles and cut her hand on the broken glass. The lab worker called for help and rinsed her cut in the sink. The responding coworker escorted her out of the intense chemical exposure and summoned additional assistance. The injured worker was treated at Campus Health Services. The chemicals flowed under a wall to an adjoining lab and to a room below which had to be evacuated. Department personnel and Risk Management & Safety addressed the spill clean-up.
Why did it happen? The flammable storage cabinet shelf was missing a support clip in the front of the shelf (see photos below) and the shelf tipped forward with the weight of the added reagents.
How can a similar occurrence be avoided? This particular flammable storage cabinet shelving support design appears problematic - the shelf clips can fall out or corrode. It is prudent to inspect your flammable storage cabinets for shelving stability and corrosion and rectify any discovered problems. With this type of shelving support design, consider epoxy-gluing the supports in place.
This incident also emphasizes a number of other significant safety issues, such as the importance of storing chemicals by compatibility. Had the chemicals been incompatible, the accident could have been much more serious (for specific advice, refer to Chemical Management Best Practices, Section 4.2, Segregation). It also stresses in importance of emergency planning. Things don't always go as planned. Ask "What would happen if…?" and be prepared to prevent such an occurrence or to take proper emergency actions (see the Emergency Procedures for more information). Lastly, be aware that some chemicals, such as chloroform, have poor warning properties and significant chemical exposures can occur without warning. The recommended exposure limit for chloroform is 10 ppm, as an 8-hour, time-weighted average. Most people can not smell chloroform until it gets above 85 ppm. With large volume spills like this, there is also the concern about fatal cardiac arrhythmias, which are a risk at vapor concentrations greater than 22,500 ppm (2.25%).
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Above – Flammable storage cabinets with problematic shelf support clips. Below Left – Problematic flammable storage cabinet shelf support clips. Below Middle – The support clips can fall out with shelf movement. Below Right – The support clips can corrode and lose their structural integrity.
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