PATEA FREEZING WORKS – SITE INVESTIGATION & FIRE Shane Reynolds Scientific Officer Taranaki Regional Council Phone: 06 765 7127 Email: [email protected] Introduction A freezing works was established on the present site, on the banks of an estuary in Patea, in 1881. It grew to become the life blood of the district, employing some 900 people at the height of processing. In the early 1980’s a national over processing capacity became apparent and with it’s reputation for industrial stoppages, Patea was one of the first works to close, ceasing operations in 1982. The effect on the town was devastating and as the years went by, the derelict and decaying works did little to improve the outlook for the residents that remained. In the South Taranaki District Council’s [STDC] consultation process for community and district plans, the issue of the derelict works regularly came up in both public meetings and submissions. There was a general feeling of dissatisfaction within the community of Patea always being referred to as, “the town with the old freezing works”. This was the catalyst for STDC approaching the Taranaki Regional Council [Council] in April 2007 and requesting assistance to investigate potential contamination of the site. With a view to its ultimate remediation an hence to submit an application to the Contaminated Sites Remediation Fund [CSRF], administered by Ministry for the Environment [MfE]. This would become the largest contaminated site investigation ever undertaken by the Council. Preliminary Site Inspection A desktop study was conducted to gather as much information as possible about the site and a preliminary inspection was made. The following issues were identified as requiring further investigation and were the basis of a “scope of work”: Underground fuel storage tanks – remove three identified tanks and quantify any residual contamination. Boiler fuel oil storage - bund and product lines to the boilerhouse Fill areas – trench, log and sample Groundwater - existing wells, install monitoring wells Asbestos – options for disposal Electrical and mechanical equipment – PCBs and tank sludges Reservoirs – sample water and sludge Fellmongery – paint mix tanks Stormwater and surface water – sample to determine quality and impacts on estuary Miscellaneous issues – coal tar seal, and dust/debris in buildings - 1 - Based on the information gathered, a list of the possible contaminants associated with historical activities at the works was developed and is shown in the table below. HAIL Activity Issue Potential contaminants 6 Building materials Roofing and cladding Asbestos Paint Lead Galvanising Zinc 36 Fuel storage Underground storage tanks and spills TPH, BTEX, PAH 41 Rail shunting Coal ash disposal Heavy metals, PAH Refuelling Hydrocarbons 46 Fellmongery Wool stripping, liming, neutralizing and pickling Chromium, manganese, copper, ammonia, sulphides, acids, sodium hydroxide, lime, formaldehyde, solvents, cyanide 49 Waste disposal Solids to fill areas, liquids to estuary Various Boilers and engine Coal ash/clinker disposal Heavy metals, PAH room Lagging Asbestos Electrical equipment Capacitors and transformers PCBs Cool stores Refrigeration plant Ammonia or ammonium hydroxide (if contacted water) HAIL: Hazardous Activities and Industries List TPH: total petroleum hydrocarbons BTEX: benzene, toluene, ethylene, xylenes PAH: polycyclic aromatic hydrocarbons PCBs: polychlorinated biphenyls An overall assessment of contamination at the site was then possible and is summarised in the table below. Contaminant Extent of Contamination Possible Exposure Routes TPH Site inspection confirmed the likely presence of 3 UST’s, age Soil/Dermal BTEX and condition unknown, extent of contamination difficult to Groundwater/Ecological risk gauge. PAH Asbestos Site inspection and previous sampling have confirmed Airborne/Inhalation extensive contamination. Heavy metals On site coal and incinerator ash disposal confirmed by past Soil PAH employee and identified at surface on site inspection, Surface water/Ecological risk extensive contamination of soil in fill areas is likely. Groundwater/Ecological risk A report and CSRF application were submitted to MfE and funding was approved for costs associated with a detailed site investigation. - 2 - The fire and detailed site investigation Progress on the investigation was significantly delayed by a fire which broke out in the early hours of Waitangi Day, 6 February 2008. The fire raged through most of the main body of buildings on the site. The Freezing and Cold Storage Buildings (predominantly timber) in the centre of the site were completely destroyed, the Slaughter House to the east was significantly damaged and a number of buildings west of the Boiler House were also completely destroyed. The fire meant that further site work had to be postponed until (i) the fire was extinguished, including actions undertaken by the Fire Service to gain access to hotspots buried beneath fallen debris; (ii) the resultant asbestos risk was dealt with to the satisfaction of the Department of Labour [DoL], to ensure that staff could continue working around the site in safety; and (iii) the scope and scale of the site investigations were reviewed to take account of the changed nature and characteristics of the site, particularly the likelihood that asbestos fibres had been released across the site due to shattering and fragmentation of asbestos sheeting and disintegration of asbestos lagging on pipework during the fire and consequent fire-fighting activities. The objectives of the detailed investigation, were to: determine whether potential contaminants identified in the preliminary report were present, establish the locations and extent of such contamination, assess the potential for off-site effects, and assist in the development of appropriate options for site remediation. Completed works Underground fuel storage tanks Contractors removed two tanks, the pits were inspected and sampled by an environmental consultant who recommended that a small amount of bedding material was also removed. At a third site no tank was found, although concrete slabs, pipework and tank straps indicated the location was correct. Excavation soon revealed what appeared to be extensive petrol residues in the soil, and approximately 100 m3 of soil was consequently removed. This was stockpiled on site along with the contaminated bedding material. It was regularly turned by excavator to aid in degradation of the hydrocarbons. Almost three weeks later, approximately 20 samples were collected from the surface of the stockpiled soil and composited for heavy metal TPH, BTEX and PAH analysis. Boiler fuel storage The boiler fuel oil tanks had previously been removed, inspection of the tank bund showed no obvious signs of soil contamination. At one point the pipework to the boiler house was rusted through and oil had leaked onto a concrete pad. This was soaked up with bedding material from the tank pits and added to the stockpile of contaminated soil. - 3 - Fill areas An 85 m long trench had been excavated parallel to the estuary to capture water run off from fighting the fire. Inspection of the trench spoil confirmed that extensive dumping of building rubble had occurred in this area. A band of dark material approximately 100 mm thick was present at a depth of around 1 m, along almost the entire length of the trench. Possibly deposits from the dumping of coal ash/clinker from the boilers, samples of this material were collected at 10 m intervals. Thirteen test pits were excavated on terraces in the south east and south west corners of the site and samples were collected from any areas of interest. Overall a total of 18 samples of fill material were collected for heavy metal and PAH analysis. Groundwater Eight existing bores on the site were inspected, samples were collected from two and analysed for heavy metals. They were considered unsuitable for use as monitoring wells due to their depth, as potential groundwater contamination was more likely to be affecting shallow groundwater. The groundwater level in four, was surveyed in order to model the groundwater flow direction. Using this information, one background and four monitoring wells were installed and one sample was collected from each well to be analysed for heavy metals, PAH and TPH. Asbestos A proposal was obtained from a specialist contractor for the removal of asbestos, demolition of buildings and reinstatement of the site. Seven samples of dust/debris were collected from the floor of safely accessible buildings across the site and analysed for asbestos. Electrical and mechanical equipment The Council was alerted to the location of a number of transformers containing PCBs. These were removed and disposed of, following appropriate procedures, however some PCB equipment could not be safely removed for disposal and remains on site. A number of tanks and vessels were identified and visual inspection indicated that most have corroded to the point where it is reasonable to assume that they contain no liquid residues, however the presence of solid chemical residues cannot be discounted. Reservoirs The main reservoir was supplied from the Patea River when the works was operational. It was pumped out of water during the fire, exposing a minimal amount of sludge in the bottom. The sludge would have consisted of silts and sediments from river water, so no samples were taken. A smaller reservoir partly beneath the south west corner of the Boiler House, contained water and a sample of the sediment on the bottom was collected for heavy metal, TPH and PAH analysis. Fellmongery – paint mix area Paint is a chemical depilatory applied to sheep skins to dissolve the fibre root allowing for easy removal of the wool. The active ingredient is sodium sulphide which is dissolved in water and thickened with a hydrated lime slurry. These ingredients react to form sodium - 4 - hydrosulphide and caustic soda in the final product which is highly alkaline. Two soil samples were collected from this area and tested for pH, to determine impacts on soil. Stormwater and surface water All water drains south, from the site to the estuary and then into the Patea River.