In two recent accidents at DOE laboratories, employees suffered lacerations on their hands and forearms during experiments that involved small quantities (less than 50 mg) of volatile materials. The injuries occurred when the samples the technicians were working with exploded, and the glass containers that held the volatile materials shattered. In both instances, the injuries could have been prevented if DOE standards for explosive safety in the laboratory setting had been followed.
Chapter II of DOE's Explosive Safety Manual (DOE/EV-06194, December 1988) contains specific guidance to ensure laboratory safety when explosive materials are being used. The manual states that in situations where explosion hazards are involved "personnel shall be protected by safety shields or the operation shall be performed by remote control".
In both of the laboratory accidents described above, the technicians knew they were working with materials that could explode. In one accident, the technician (who was not wearing gloves) was working with a mixture of powdered zirconium and potassium perchlorate. When the accident occurred, he was using a spatula to transfer the material from the beaker. Apparently, using the spatula created enough agitation to ignite the mixture. The beaker exploded in the technician's hand, and he suffered a number of hand/ann lacerations.
The second accident occurred during a "compatibility test" that involved mixing titanium metal powder with an explosive compound. The end result of the "test" was an extremely sensitive mixture. During the final stages of mixing the materials, the technician was preparing to break the glass melting-point tube to shorten it. In that precise instant, the sample inside the tube exploded (probably because of friction or static electricity), shattering in the technician's hand. Because he had not taken the precaution of wearing gloves, the technician's hand was lacerated to the extent that the underlying muscle was exposed.
Fortunately, since the technicians knew that the materials they were working with were extremely volatile, they had taken some safety precautions. Both technicians were wearing plastic shields to protect their faces and eyes, for example, but neither was wearing gloves to protect their hands and forearms.
In both accidents, wearing gloves would have provided some protection for the technicians' hands and arms. However, had the guidance of the DOE Explosive Safety Manual regarding the use of safety shields and forceps (or other remote handling devices) been followed, the technicians who were involved in both accidents certainly would have escaped injury.
In addition to general laboratory safety guidance, the DOE Explosives Manual (page II-67) also includes a table that lists acceptable safety shields and the minimum distance personnel should put between themselves and various quantities of explosive materials. This table is reprinted on the reverse page.
When working with volatile materials, there is always the potential for an "explosive reaction." Thus, all DOE laboratories where operations include work with explosive materials should ensure that laboratory personnel are aware of and obey the standards for explosive safety described in the DOE Explosives Manual. Implementing the following recommendations will also protect laboratory workers who handle volatile materials from serious accidents or injuries.
Minimum
distance from Explosives
Shield explosive, cm limit
---------------------------- ------------- ----------
Leather gloves, jackets or -- 50 mg
coats, and plastic face
shields
3 mm tempered glass 8 50 mg
7 mm Lucite/equivalent 15 2-1/2 g
material
20 mm Lucite/equivalent 15 10 mg
material
15 mm laminated resistant 20 20 g
glass
25.4 mm Lexan/Lexguard 30 50 g
2 units each of 25.4-mm 30 50 g (steel
plate glass laminated with confined)
12.4-mm polycarbonate
with a 9.5-mm air gap between
units (glass sides
facing the explosive)
*Taken from Chapter II, Section 21 (page II-67) of DOE
Explosives Manual (DOE/EV-06194, December 1988).