Response to Oil Spills

How we respond to oil spills
In the event of a spill, NAOC’s in-house response team mobilizes for confirmation and verification of spill site. The spread of spill is contained by deploying containment measures. The leaking facility is either isolated/shut down or depressurized as applicable repairs are carried out. Following containment and repairs, the impacted site is cleaned up and a post clean up inspection is conducted with Government regulatory agencies where soil sampling and analysis of site are carried out.

Remediation is based on the result of the laboratory analysis of samples collected after the clean-up. In cases remediation is required, the method most frequently adopted is RENA (Remediation by Enhanced Natural Attenuation).

Response to Oil Spills

Steps following an oil spill event are managed by NAOC as follows:

  • Spill verification and notification
  • Containment/Recovery
  • Joint Investigation Visit (JIV) with Government Regulatory Agencies and Communities
  • Repair
  • Delimitation survey of impacted area
  • Clean up of impacted site
  • Post Clean up Inspection (PCI) with Government Regulatory Agencies and Communities
  • Sampling/Analysis for close out
  • Remediation (if required)
  • Close out Certificate provided by Government Regulatory Agencies


In particular, the investigation process includes the following steps:
(a) The JIV team comprises of NAOC, Department of Petroleum Resources (DPR), National Oil Spill Detection and Response Agency (NOSDRA), State Ministry of Environment (SMENV) & Community representatives that visit the site to:

  • Confirm the cause of spill through visual observation and Ultrasonic Thickness Measurements (UTM) result
  • Determine the quantity of oil spilled through quantitative assessment which normally includes the extension of area impacted and the depth of oil, as well as porosity of soil (when applicable)

(b)  The JIV Report/Sheet are duly signed by all participants
(c)  Repair of the leak point is carried out immediately after the JIV
(d)  Delimitation survey of the impacted area by the relevant participants is carried out immediately after the repair of the leak point
(e)  The Oil Spillage/Leakage Report document is completed with the information from the JIV report and additional input on spill site status from in house field visits.

Response to Oil Spills

How we clean up the oil spills
The clean up method employed by NAOC for the clean up of oil impacted sites involves the following:

  • Skimming, recovery and transportation of all free-floating oil from the spill site to the nearest company crude oil facility or company approved treatment site for incineration
  • Cutting/clearing of oil stained vegetation from the impacted area where necessary and transportation of the waste to a treatment site for incineration.
  • Scraping, gathering and transferring of all contaminated soil/oily waste to an incineration site
  • General tidying up of the entire impacted area is carried out to the extent that there would be no oil on sediments or visible oil sheen on water.
  • After the clean up is completed, a Post Clean up Inspection (PCI) is carried out with Government Regulatory Agencies (GRA) where samples are collected for analysis. The site is closed out if the results of the analysis indicates that no further remedial action is required.

There is regular monitoring of the spill site by NAOC during the clean up activities to ensure that the cleanup is executed in line with the scope of work and regulatory standards.

Construction of windrows

How we remediate the oil spills
NAOC remediates contaminated sites (soil) using Remediation by Enhanced Natural Attenuation (RENA), which is an integrated use of Bioremediation and Land-farming techniques. The principle for the application of RENA is based on the fact that:

  • The hydrocarbon compounds in the spilled oil undergo biodegradation under suitable bio-physico-chemical conditions.
  • Various forms of activities under RENA promotes these conditions, and the hydrocarbon compounds biodegrade gradually to give rise to CO2, H2O and biomass.

The RENA process involves the following:

i.  Site assessment: Surface visual inspection of the site, sampling (sample collection and analysis, results of analysis).
ii.  Site preparation:  Clearing of the site is done manually by cutting down and clearing dead logs for easy accessibility.
iii.  Soil preparation: Tilling and homogenisation of impacted soil aimed at exposing the impacted soil to atmospheric aeration.
iv.  Construction of ridges: Construction of ridges in a windrows fashion to expose deeply contaminated soil to the surface for aeration and eventual attenuation through biodegradation.
v.  Soil amendment:  Nutrients application to contaminated soil to enhance the quality of the soil.
vi.  Monitoring:  The area will be monitored for a period of four months after soil amendment and samples collected and analysed.
vii.  Project close out: Site to be closed out only when plants and vegetation have regenerated and the Total Petroleum Hydrocarbons (TPH) and other contaminant levels have reduced in line with the Nigerian standards.

Re-planting of vegetation

Last updated on 16/11/18