Timber Treatment Site

Fraser Thomas has investigated a significant timber treatment site, situated on reclaimed land next to Whangaroa Harbour in Northland, which was used as a sawmill since the 1800s.

The investigation involved a comprehensive desktop study (Council records, aerial photos, interviews, certificates of title), site walkover and visual appraisal, soil and water sampling and reporting.

We found that the site has been used for timber treatment since the 1950s, involving copper chrome arsenate (CCA), pentachlorophenol (PCP) and boron chemicals.  Sampling found low level arsenic and chromium contamination across parts of the site and hydrocarbon contamination also present in former under-ground storage tank location.

We then developed a Remedial Action Plan which recommended:

  • Liquid in timber treatment equipment and tanks to be removed by licensed liquid waste contractor
  • Timber treatment equipment and tanks to be removed from site
  • Hydrocarbon contaminated soil to be excavated to an approved landfill
  • Areas of Arsenic/chromium contamination to be capped or removed from site to an approved landfill
  • Validation sampling to be undertaken as necessary.

Expertise provided:

  • Contaminated Land

Project cycle:

  • Preliminary site investigation
  • Detailed site investigation
  • Risk assessment
  • Remedial Action Plan