While working a station duty shift on 1-4-2013, I filled the SCBA cascade system with the compressor.
Unit was running in ‘auto’ mode, and I saw the system was almost full. At about 1530, I deemed it ‘close enough’ and manually shut the compressor down as the end of the work day was approaching. System had not yet reached the auto shutoff point. All tank valves were closed and compressor was off. Power was locked out. I was bleeding off line pressure with the fill station and bleeding condensate from the compressor drains. I was standing next to the cascade tanks completing logs on my clipboard when the burst disk on tank #3 suddenly failed. System rapidly vented causing an extremely loud noise and kicking up dust and loose debris on the area. Straps, cords and hoses in the area began to whip around. The sudden release startled me and I ran from the area as I had no idea what just occurred. I realized it was a system failure of some sort and realized i needed to get away to a safer area. Once i left the area, I covered my ears and looked back at what has happened. At this time I saw the valve on tank 3 was frozen indicating rapid depressurization. Tank continued to vent for a few minutes.
The burst disk on tank #3 was stamped for 4000psi. The other tanks had stampings indicating 5000psi. This system is operated at 3500-3600 PSI.
I tagged then tank out of service.
About a half hour later, I decided I should get my ears examined as they were still hurting and ringing. Chief XXX gave me authorization for treatment form. Occupational clinic was closed at this time. I went to XXXXXXXX ER to be evaluated.
Exam revealed right-side eardrum rupture / perforation. Discharge instructions included seeing an ENT specialist in a few days for follow up. Physician wrote prescriptions for an antibiotic and pain medications.
Follow-up exam with an ENT physician revealed 20dB hearing loss in affected ear. Hearing loss is believed to be temporary, and should return in several weeks.