Moss Landing Ongoing Work: What are the contaminants of concern?

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The list of contaminants of concern for the site was based on:

• what were in the batteries,
• contaminants released during fire (combustion), and
• what was present in the Moss Landing 300 structure.

Under our legal order, Vistra must monitor and sample air to ensure contaminants of concern are not moving off-site during work. 
Air monitoring looks for:

• Hydrogen fluoride (this is a by-product of battery fires)
• Particulate Matter 2.5 and 10 (as an indicator for metals, as well as for dust movement in general)
• Volatile Organic Compounds (VOCs)
• Lower Explosive Limit (this checks for high concentrations of explosive gases)
• Percent oxygen
• Carbon monoxide
• Hydrogen cyanide (this is a potential on site concern for workers from burning plastic components of the batteries should they catch fire)

Air sampling looks for:

• Asbestos
• Cobalt
• Manganese
• Nickel
• Copper
• Lead
• Aluminum
• Lithium

Because air monitoring and air sampling accomplish different goals, the contaminants are different.

• Air monitoring gives immediate results and is for worker and community safety.
• Air sampling shows average concentration of a contaminant over a time period, but takes many hours.

Note: When Vistra renovated the ML300 building, much of the asbestos was removed (this is called “asbestos abatement”) from the building. Only small amounts of asbestos in a limited number of materials were left on property.

Under our oversight, Vistra is taking measures to ensure any contamination on the property does not leave the site until the waste is properly managed for transport and disposal.

Air monitoring and sampling around the site and in the community since the fires confirms this.

Is EPA testing for dioxins?

Dioxins are produced in many ways, such as through power plant operations, agricultural operations, etc. Without a long-term study and risk assessment, it is difficult to determine if dioxins in the surrounding environment are a result of the January 2025 battery fire at Moss Landing, and whether the exposure constitutes a risk to human health. EPA’s role in this response is primarily focused on addressing the threat to human health and the environment by removing the batteries that remain at the site.

Did EPA sample for black carbon?

Black carbon (soot) is part of PM 2.5 (particulate matter smaller than 2.5 microns), which is measured in air monitoring. Since the fire, we have not seen levels of PM2.5 that would be of concern to the community’s health.

Related Questions

• Moss Landing Ongoing Work: Can the building be covered or tented?
• Moss Landing Ongoing Work: How is the air monitoring and air sampling data being used to protect the community and the environment?
• Moss Landing Ongoing Work: How will you control dust and particles during operations?
• Moss Landing Ongoing Work: How will you prevent the contamination from moving off site when it rains?
• Moss Landing Ongoing Work: How did EPA and Vistra determine the truck routes to be used for transporting material off-site at Moss Landing? Why were other truck route options not selected?