Use Recapture target for every fumigation event
Start date10
Containers 95% 28 April 2021
Fumigation under sheets 80% 1 October 2022
85% 1 October 2027
90% 1 October 2032
95% 1 October 2037
Ship-hold 80% 1 October 2025
85% 1 October 2030
90% 1 October 2032
95% 1 October 2037
(3) The recapture targets apply to every single fumigation event, where a fumigation event is defined as the fumigation of one enclosed space. They are not to be averaged between events, by location, by operator, or nationally; nor by time across any of these groupings.
(4) An annual report detailing progress towards the recapture targets is to be provided to the Environmental Protection Authority by 30 June of each year.
13.52 In addition to considering the proposed amendments to the recapture controls, there are other issues that need to be considered if the recapture target is to be changed, including buffer zones, and monitoring, recording, and reporting requirements, to reflect the changes in risk associated with a change in recapture threshold. The DMC should consider whether these issues can be adequately addressed by the controls proposed by the EPA.
Table 14 2010 reassessment's minimum buffer zones
Use Minimum buffer zone (m)
Containers (total volume less than 77 m2 in any 60-minute period) 10 Containers (total volume of 77 m2 or more in any 60-minute period) 25
Fumigation under sheets 50
Ship-hold (less than 1,000kg in any 24 hour period) 50 Ship-hold (1,000kg or more methyl bromide in any 24 hour period) 100
13.55 As the 2010 DMC considered that recapture technology would significantly reduce the amount of methyl bromide released following a fumigation they decided that these buffer zones need not apply when recapture technology was used. The recapture to 5 ppm would provide the protection to public health that the buffer zones were designed to achieve.
Reissued approval
13.56 Following the regulatory changes in 2017 (see paragraph 2.32), the buffer zone control was moved to regulation 14.38 of the HSW (HS) regulations, with the above minimum buffer zones in Table 4 of Schedule 18. Consequently, the buffer zone controls were only included in the July 2019 reissued approval by reference to the HSW (HS) regulations.
13.57 In the HSW (HS) regulations, the buffer zones only apply when recapture technology is not used. Recapture technology is not defined in the regulations.
Applicant’s proposal
13.58 The applicant asked for refinements to strengthen buffer zone requirements at the end of the recapture process.
13.59 Although they did not propose any new buffer zones in their application, they report that their air dispersion modelling of log stack and ship hold fumigations found that air concentrations were at acceptable levels within 20 m.
Submitters’ proposals
13.60 BOPRC, in their submission consider that buffer zone distances should not be reduced and that they should be “based upon real world, worst case data on exposure risks”.
13.61 At the time of providing their submission, Northland Regional Council (Submission127560) did not set site specific controls as they considered methyl bromide fumigation to be a permitted activity under the Resource Management Act 1991 (RMA), though noted that this was under appeal11. They consider that methyl bromide controls are best set at a national level.
11 This appeal has subsequently been heard, with all parties now agreeing that methyl bromide fumigation will be a discretionary activity (https://environmentcourt.govt.nz/assets/Documents/Publications/2020-NZEnvC-102- Public-and-Population-Health-Unit-of-the-Northland-District-Health-Board-v-Northland-Regional-Council.pdf)
WorkSafe comments
13.62 WorkSafe considers that the controls in the current regulations may not be adequate to manage the risks to workers and bystanders when recapture technology is used.
13.63 They note that their monitoring programme has identified the potential for the 1-hour TEL to be breached at the port boundary. WorkSafe recommended that the buffer zone distances should not be reduced even when recapture is used, and the buffer zones are reassessed in response to validated modelling.
13.64 Although the minimum buffer zones set in the 2010 reassessment, and transferred to the HSW (HS) regulations would not apply if recapture is used, they note that the person conducting business or undertaking (PCBU) must still meet the requirements of regulation 14.39(1):
A PCBU with management or control of quarantine or pre-shipment fumigation using methyl bromide must ensure that it is not used in a manner that results in a concentration of the substance in the air at the boundary of the buffer zone that exceeds the tolerable exposure limit set for methyl bromide.
13.65 In such a case, the duty holder would need to put a buffer zone in place to ensure that the requirements of regulation 14.39(1) is met based on their own modelling and measurements of methyl bromide air concentrations.
Discussion
13.66 From the air dispersion modelling conducting on behalf of the EPA as part of the evaluation of this reassessment application (see paragraph 7.53), the minimum distances at which 1-hour TEL needs to be met in order to protect public health are presented in Error! Reference source not found.. These distances are larger than the equivalent minimum buffer zones from the 2010 reassessment and HSW (HS) regulations (see Table 14).
13.67 The buffer zones for the use of methyl bromide should, therefore, be larger than those currently set. The suggested new buffer zones are presented in Table 15. Those for “No recapture”
should be implemented as soon as possible, even if the DMC decide to vary the recapture definition and the deadlines by which it would apply.
13.68 The only model to consider no recapture is that by TAS. This model has therefore been used to calculate the minimum buffer zone in the “no recapture” scenario.
13.69 The Golder model already incorporates the two-hour time gap between different ship holds being vented. As this model was prepared for a resource consent application, the input parameters also better represent the methyl bromide fumigation activities at the Port of Tauranga.
13.70 Although the New Zealand air dispersion guidance document recommends reporting the 99.9th percentile as the maximum concentration for modelling results, we note the advice from methyl bromide modelling experts at TAS and ASG that the 100th percentile better represents the situation for methyl bromide. ASG have stated in their reviews of the Golder report that the 100th percentile better represented the available monitoring data. For these reasons, we have used the 100th percentile isopachs from the Golder report.
13.71 Buffer zone distances are defined in the Hazardous Substances (Hazardous Property controls) Notice 2017 (“HPC Notice”) as the horizontal distance from a downwind sensitive area.
Although not explicitly stated in the HPC Notice, we consider that this includes sensitive areas +/- 45 degrees downwind of the prevailing wind direction at the time of fumigation.
13.72 In this case, a sensitive area is considered to be a place where non-occupational bystanders might be present, including but not limited to those in occupied residential and
commercial/industrial properties, public open space, and marae and other Māori facilities.
13.73 The DMC may wish to consider if the large buffer zones, particularly for fumigation in ship holds, are practicable. If the DMC decides to not set these as controls, then the EPA Staff advice is that the adverse effects from the release of methyl bromide following ship hold fumigations exceed the benefits.
Table 15 Recommended buffer zones (based on 120 g/m3 of methyl bromide) Recapture
scenario
Use Minimum
buffer zone (m)
Source model
No recapture Containers (total volume less than 77 m2 in any 60-minute period)
10 2010 reassessment decision
Containers (total volume of 77 m2 or more in any 60-minute period)
25 2010 reassessment decision
Fumigation under sheets 625 TAS, log stacks, 100th percentile, 120g/m3
Ship-holds 1,900 TAS, ship holds, 100th
percentile, 120g/m3 80%
recapture
Containers (total volume less than 77 m2 in any 60-minute period)
10 2010 reassessment decision
Containers (total volume of 77 m2 or more in any 60-minute period)
25 2010 reassessment decision
Fumigation under sheets 300 Golder, log stacks, 100th percentile
Ship-holds 1,000 Golder, ship holds, 100th
percentile Staff recommendation
13.74 The discussions in paragraphs 13.58 to 13.73 are incorporated into the following recommended control, which would use section 77 of the HSNO Act to impose a buffer zone distance in accordance with clause 51(1) of the Hazardous Substances (Hazardous Property Controls) Notice:
(1) The following buffer zones are set for the use of methyl bromide.
Use Minimum buffer zone (m)
No recapture 80% recapture Containers (total volume less than 77 m2 in any
60-minute period)
10 10
Containers (total volume of 77 m2 or more in any 60-minute period)
25 25
Fumigation under sheets 625 300
Ship-holds 1,900 1,000
(2) In this case, a sensitive area is considered to be a place where non-occupational bystanders might be present, including but not limited to those in occupied residential and
commercial/industrial properties, public open space, and marae and other Māori facilities.
13.75 The requirements of the HSW (HS) regulation 14.39(1) would still apply (see paragraphs 13.64 and 13.65).