To gauge the metallic emissions and potential air pollution in Los Angeles County, the Southern California Air Quality Management District (SCAQMD) began installing community monitoring devices and found two metals of concern: nickel and hexavalent chromium (Cr(VI)). In order to reduce the amount of hexavalent chromium, the SCAQMD decided arbitrarily to set an allowable limit of 1 ng/m³.

The problem with the SCAQMD’s decision is that a 1 ng/m³ defies logic, science and the rest of the world. Here are the allowable levels of hexavalent chromium by other agencies and the European Commission (See Accompanying Video):

• The Occupational Safety and Health Administration (2006) set a 5,000 ng/m³ limit for workers in general industry.
• The European Commission – Scientific Committee on Occupational Exposure Limits (2017) set a limit of 1,000 ng/m³.
• National Institute of Occupation Safety and Health, Center for Diseases Control (September 2013) recommended an exposure limit of 200 ng/m³ for health protection.

Health-based hexavalent chromium guidance values have also been developed for residential exposures by the Agency for Toxic Substance and Disease Registry (ATSDR) and the Office of Environmental Health Hazard Assessment (OEHHA) of the California Environmental Protection Agency.

The Agency for Toxic Substances and Disease Registry, which is part of the Centers for Disease Control, has set a minimal risk level (MRL) for long-term continuous exposure to Cr(VI) at 300 ng/m³.

The Office of Environmental Health Hazard Assessment of the California EPA set a reference exposure level (RSL) for hexavalent chromium at 200 ng/m³.

In SCAQMD’s monitoring of hexavalent chromium, the measured levels have never come close to these health-based values. The monitors show hexavalent chromium at less than 1 ng/m³ on average during the past several months in Paramount. If you don’t believe us, look for yourself:

AQMD Paramount Readings:

http://www.aqmd.gov/docs/default-source/compliance/Paramount/expanded-monitoring-data-and-map.pdf?sfvrsn=307

AQMD Compton Readings:

http://www.aqmd.gov/docs/default-source/air-toxics-initiative/compton/monitoring-data-map.pdf?sfvrsn=77

The biggest concern is that the issue is being guided by emotion or a desire for a particular outcome, while science takes a backseat. The Los Angeles County of Public Health must conduct their SCAQMD air monitoring evaluation based on sound science, not personal agendas