A hydrocarbon spill was detected on the coast near the port of Sillamäe. The inspection authorities responsible for environmental protection visited the site and discovered that the pollutant had escaped from a stormwater outfall of the neighbouring boiler room. The wind, which was blowing towards the ground, confined the pollution spill: 150 m of coastline were contaminated. A floating boom was set up to recover the hydrocarbons along the coast for storage in 200-litre barrels.
The plant designated to treat the 2,400 kg of fouled water and materials collected at the site estimated that 240 kg of hydrocarbons were contained in the spill, and these were produced from the bituminous schists found in the region, which also carried traces of phenol: the phenol concentration measured in discharged products varied from 0.04 mg/kg to 0.06 mg/kg.
The authorities concluded that at the adjacent oil terminal, the sump on the stormwater system oil separator in the rail tanker transfer station had not been drained for some time. Filling level monitoring and drainage operations had been scheduled in the emergency plan for this site but had yet to be formalised in a written procedure. Hydrocarbons mixed with rainwater reached the terminal’s stormwater drains and then entered the boiler room pipe network, from where water is normally discharged into the sea via an outfall. A vacuum distillation effluent was recently discharged during rail tanker transfer operations, although hydrocarbon accumulation in the oil separator sump would have predated this incident.
Subsequent to this event, the stormwater system operator (not the same entity as the oil terminal) was levied a 100% tax increase on effluent discharge (from 13,360 to 26,720) and required to pay another 4,000 in fines as the party liable for environmental discharges. The oil depot installed alarms on its drainage network.