Smell of unknown origin spreads through Costa Mesa and Huntington Beach; AQMD investigating

A strong odor of unknown origin traveled through Orange County on Thursday night, officials said.

The fire departments in Huntington Beach and Costa Mesa fielded reports about the odor, which was described as a chemical smell, and Huntington Beach officials said it occurred in several other cities as well.

“Fire crews responded to investigate and the source is unfounded,” the Costa Mesa Fire & Rescue Department said on Twitter.

Brynne Palmer, who lives in Costa Mesa, told KTLA that her eyes began to water when she stepped out to walk her dog.

The South Coast Air Quality Management District said Friday that the agency has dispatched inspectors to investigate the source of the odor.

Speculation on social media ranged from offshore drilling to pest control.

However, officials from the Orange County Mosquito and Vector Control District said in a statement Friday that the product they use to spray for mosquitoes is water-based and odorless and that they have not conducted aerial spraying in the area.

Strong odors of unknown origin have permeated the region periodically for the past several years. In some cases, officials said they believed the smell was coming from offshore.

Occasionally, an odor is carried several miles inland, “where it drops down and that’s when people start smelling it,” Costa Mesa fire Capt. Chris Coates said during a similar episode in March 2016.

Mysterious smells recurred later in 2016 and in 2017, causing frustrated residents and city officials to demand answers.

In each case, officials have said the odors pose no immediate danger to life, though residents have reported headaches, nausea and sore throats.

Odors can be reported to the AQMD at (800) 288-7664. Any abnormal medical symptoms should be reported to 911, officials said.

UPDATES:

1 p.m.: This article was updated with information from the South Coast Air Quality Management District and Orange County Mosquito and Vector Control District.

This article was originally published at 7:50 a.m.