An investigation into a nauseating stench that plagued Carson, California, for months found that a nearby fire released chemicals into a local channel, creating the odor. Now, Los Angeles County and four other companies are facing violations for their role in the incident, the South Coast Air Quality Management District announced Friday. On September 30, a large fire ignited at a warehouse in Carson that contained beauty and wellness products from the companies Virgin Scent Incorporated and ArtNaturals and Day to Day Imports Incorporated, the investigation found. The fire lasted for multiple days. Following the fire, chemicals from the stored products, including ethanol, passed through the city’s sewer system and into the Dominguez Channel, causing elevated levels of hydrogen sulfide to be emitted into the air, the investigation found. At one point, the hydrogen sulfide levels in the local waterway were about 230 times higher than California’s nuisance standard. According to the Centers for Disease Control and Prevention, hydrogen sulfide gas is colorless, has a strong odor of rotten eggs and can cause irritation to the eyes and respiratory system as well as coma, convulsions, dizziness, headache and insomnia upon exposure. The gas is created by rotting plants and other materials in the water, according to the Los Angeles County Public Works. The Dominguez Channel in Carson, California. KCBS The two companies, their parent company Prologis Incorporated, Liberty Properties — the owner of the warehouse — and the county of Los Angeles are accused of causing a public nuisance that violates a section of California’s Health and Safety Codes as well as a rule from the South Coast Air Quality Management District. The lingering stench cost the Los Angeles Department of Public Works an estimated $5.4 million to remedy. Officials said they began receiving reports of foul odor in the city on October 3 and have since responded to more than 4,600 complaints from residents throughout Los Angeles County. One Carson resident said at one point the smell was so bad that they wore a face mask while inside of their own home, CBS Los Angeles reported. Another said the fumes worsened their preexisting health conditions. KCBS “I’m in remission from cancer so that makes it worse, and I have asthma,” resident Hermel Rivera told CBS Los Angeles. Thousands of impacted residents were relocated to hotels in surrounding cities due to the lingering odor, and hundreds of air purifiers were distributed, Carson Mayor Lula Davis-Holmes said. The mayor and the Los Angeles County Board of Supervisors each declared a local emergency for the stench in October. The five notices of violations can result in civil penalties should the violators not establish measures that reduce emissions or prevent future violations, regulators said.