On February 7, 2017, an employee, 50, was making preparations to replace the relief valve of a 1,000-gallon ammonia (NH3) tank. The incident investigation reported that the tank was empty of liquid NH3. However, it contained approximately 80 psi of vapor pressure.
The employee set up a 30-gallon drum that contained water and affixed it to the nurse tank by way of a hose. He then turned the relief valve of the tank to bleed the vapor pressure into the drum. The vent of the drum was not completely clear, causing the bottom of the drum to burst and become airborne.