Moerdijk requiem

10 February 2012 - Freak accident

Moerdijk remnant pump.gifThe Chemiepack company is bankrupt, its management is still facing jailtime (earlier report here) and the official report into the Moerdijk disaster (chemical packaging/mixing company went up in flames, no one was hurt though), the publication of which Chemiepack tried to block, is finally out (PDF, 5MB in Dutch). So what did the investigators find and what was Chemiepack trying to hide? A lot it seems.
The report explains in detail how the fire started: someone was transferring resin from a container to an industrial dispenser with the aid of a pump, because of the cold the pump got clogged and the same someone then defrosted the pump with a gas burner (against regulations of course). This ignited a overflow container filled with xylene, used to clean the pump. Operators on the scene then attempted put the fire out but failed because a) a powder fire extinguisher did not work and b) water was used which only helped dispersing the burning organic material.
To make matters worse no one thought of switching off the pump and the pipe carrying the resin to the dispenser burst due to a faulty weld, causing a spray of resin (up to 150 liter per minute) that was ignited by the burning xylene. The burning resin then made sure that the plastic containers in the vicinity of the fire collapsed adding their inflammable content to the fire as well. Nice detail: laboratory testing showed it is not possible to ignite the resin directly with a gas burner, burning xylene is a necessary go-between.
The fire department was then called in and their response was also assessed in the report. Contrary to the early news reports the fire department at an early stage decided to let the site burn out in a controllable way. They did not use water to try to put the fire out but used water merely to guard specific objects, for example a sea container filled with isopropyl alcohol. In that sense the fire fighters are vindicated. Chemiepack management on the other hand is blamed for ignoring all sorts of safety regulations. The pump in question did not just malfunction in the winter of 2011, it did malfunction every winter.
One of the recommendations relevant to us chemists concerns the use of plastic containers (up to 1000 liters) for packaging hazardous chemicals. They are often made from polyethylene which is a material resistant to chemicals but which melts already at 105°C. A burning wad of newspaper is sufficient for ignition.
With respect to the various chemicals stored on the site the report specifically mentions one chemical called 2-ethylhexyl nitrate present in a quantity of 160 tonnes. This chemical is used as a fuel additive and decomposes and ignites at 130°C. Apparently the owner knew of the hazards but none of the Chemiepack employees did.
And why did the pump clog up in the first place? The pump ran on compressed air and the exhaust apparently made a hell of a noise. To keep noise levels down an exhaust muffler was added. Expanding air efficiently cools this muffler and in combination with an already cold January day and condensation water the muffler clogged up with ice and reduced in turn pumping action to zero. Enter the gas burner.