Many accidents reported from paper mills have much in common with this incident. Microorganisms in the process water with pulp produce hydrogen gas that mixes with air to form an explosive atmosphere. The ignition source is typically sparks produced by hot work, but ignition by electrostatic discharges in a cloud of mist in a storage tower has also been reported (see Explosion Caused by Microbial Hydrogen Formation).

Provided the hazard posed by bacterial hydrogen production has been recognized, there are several preventive and/or mitigating measures that can be considered for reducing the risk:

It is advantageous to avoid anaerobic and stagnant conditions in the solution by providing sufficient circulation and/or aeration (bubbling air through the solution), but this requires monitoring and could result in foaming or generation of biogas.
The formation of an explosive atmosphere may be avoided by providing sufficient natural or forced ventilation to keep the hydrogen concentration below the lower flammability limit (LFL), or by using an open-top floating roof tank to remove the space where an explosive mixture could form.
Forced ventilation can be used, but this solution requires monitoring, and care must be taken to avoid introducing a potential ignition source.
The free space above the liquid level can be blanketed with an inert gas to prevent the formation of an explosive mixture, but this is a relatively expensive solution that requires monitoring, and the inert atmosphere will promote anaerobic conditions that favor bacterial hydrogen production.
Strict enforcement of hot work procedures, including gas measurements and the use of non-sparking tools, may prevent certain ignition sources, and especially those that are directly associated with personnel risk.
Technical solutions such as grounding to prevent build-up of electrostatic charges and installation of flame arresters on all openings in the tank to prevent ignition by lightning, etc. can also reduce the risk, but the possibility of having an explosive atmosphere inside the tank should still be regarded as a severe hazard.
Risk management strategies should include a continuous focus on preventive maintenance, mandatory safety training for all workers, regular reviews of risk assessments, and learning from previous accidents in related industries.