Questions and answers - Stage 3 Orica Botany remediation project

These questions and answers cover the decontamination, site preparation and removal of the Temporary Emissions Control Enclosure (TECE) and removal of associated Emissions Control Systems (ECSs).

1. When will Orica pull down the enclosure?

Orica is likely to start removing the enclosure in June/July 2014. This timing is dependent on the EPA:

  • issuing a licence variation that specifies additional requirements to ensure that the decommissioning of the enclosure does not have an adverse impact on the environment and human health
  • finalising its reviews of all relevant monitoring data.

2. How long will it take?

Decommissioning and removing the building will take about 10 to12 weeks. Construction of the capping system (i.e. concrete slab) and below-ground cut-off wall is expected to take another 12 months.

3. What are the phases of this project?

Stage 1: August–November 2013: Completed

  • Blocks A and M excavation and replacement of new/remediated soil.

Stage 2: September–December 2013: Completed

  • Block G targeted excavation and removal of mercury contaminated soil and replacement of new/remediated soil.

Stage 3: January–December 2014: In progress

  • Decontamination, site preparation and removal of the TECE and removal of associated ECSs.

Stage 4: January–June/September 2015

  • Construction of cut-off wall
  • Installation of capping system

4. How can we be sure that air emissions will be safe when the enclosure is removed?

Remediation of the soil within the enclosure has been completed in accordance with EPA’s Management Order. The highly contaminated soil has been removed and properly disposed of off-site.

The EPA has conducted rigorous reviews of the monitoring data from inside and outside the enclosure and conducted inspections inside the enclosure itself. Monitoring inside the enclosure shows that the mercury levels are now low and decreasing and there is no longer a need for personal protective equipment.

Monitoring of mercury levels will continue so that in the unlikely event that emission levels rise, immediate management actions can be employed to protect the environment and human health.

5. What is the purpose of the mercury limits on Orica’s licence?

The emission limits in the licence are set well below the levels required to protect the environment and human health. In addition, the licence specifies ‘action levels’, at which Orica is required to implement various management actions to ensure the mercury levels remain below the licence limits.

6. What are the average mercury levels inside the TECE now?

The average reading inside the enclosure for the week starting 28 April was 1.7 micrograms/m3 and the lowest reading was 0.7 micrograms/m3. Modelling using World Health Organisation standards indicate the shed can be removed safely once the levels inside the enclosure fall below about 50 micrograms/m3

7. Are these levels okay for workers inside the enclosure?

The current levels mean it is now safe for workers to move around inside the enclosure for a full-working day without using any breathing apparatus. 

The WorkCover time-weighted average limit for exposure to mercury as elemental vapour is 25 micrograms/m3 as an 8-hour average. 

Time-weighted average (TWA) means the maximum average airborne concentration of a substance when calculated over an 8-hour working day, for a 5-day working week.

8. Is NSW Health satisfied that risks to the public have been adequately minimised?

NSW Health has informed the EPA that:

  • it expects that enforcement of compliance with the licence conditions for decommissioning the enclosure will minimise any risks to public health
  • continuous monitoring of mercury concentrations in the air at the 3 sensors located near Botany Industrial Park boundaries will be important in detecting any release of mercury vapour which might affect the local community.

For more information on mercury exposure and health, see the Public Health Unit’s environmental health web page.

9. Will the EPA also conduct its own monitoring?

Yes. The EPA is in the process of commissioning an ambient air monitoring scientist to conduct independent monitoring. This will involve an ambient air monitoring station being installed close to the enclosure. This independent monitoring will be conducted for a period before the shed is removed, and then for a period during its disassembly.

The EPA will closely review all monitoring data.

10. What is Orica doing to communicate with the community?

Orica has informed the EPA that it intends to provide information to the community in a number of ways. This includes:

  • publishing an advertisement in the Southern Courier
  • posting a former chlor-alkali plant (FCAP) Stage 3 fact sheet on its website
  • conducting a letter drop to its neighbours in Denison Street
  • providing the Community Liaison Committee with a newsletter.

Orica has also stated that it will provide community members with a number of avenues to seek more information and have their concerns answered.

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