Operators of the Chiquita Canyon Landfill in Castaic have been ordered to reduce odors that have led to residents complaining and even falling ill.

So far this year, the South Coast Air Quality Management District has received 2,100 odor complaints that investigators traced back to the landfill. As a result, AQMD has issued approximately 60 notices of violations for public nuisance.

The agency’s investigation found that the landfill gas contained elevated levels of dimethyl sulfide, which its gas treatment system is currently not designed to remove, officials said. A subsurface chemical reaction was determined to be the root cause of the issue.

On Wednesday, an order of abatement was issued to further address the issue, including requiring the facility to investigate the cause of the chemical reaction and to take steps to reduce the impact to the community until a final solution is achieved that completely eliminates to odors.

Landfill officials are required to:

  • Conduct odor surveillance at least twice daily during operating hours at 32 locations around the landfill until a three-week period passes without receiving a notice of violation. Odor surveillance will resume if AQMD receives a notice of violation.
  • Maximize the use of specified landfill gas flares for combustion of landfill gases, with requirements to sample, analyze, record and report compounds combusted in each flare.
  • Submit a monthly written report on the landfill operation, landfill gas flares and treatment system, and efforts to resolve the total sulfur concentration in the landfill gas.
  • Organize a committee of experts to investigate and find the cause and solution to the chemical reaction causing the elevated levels of sulfur and report to AQMD detailing the findings by next April.
  • Expand the gas well system and monitor each gas collection system at least monthly for temperature.
  • Inspect the landfill cover each operating day, make needed repairs and install a geosynthetic cover to limit the migration of landfill gas from the site.
  • Maintain trash odor mitigation efforts by using fans, odor neutralizing misting systems, using proper hauling sequencing and cover and providing regular training to staff on odor control.
  • Maintain and update on a weekly basis an odor mitigation section on its website, including providing Spanish translation.