Environmental Testing

Air, water, and soil testing by multiple agencies have found no threats to public health or agriculture to date. Below is a summary of findings from the testing, sampling, and monitoring efforts conducted by various agencies and organizations.

Surface & Soil Sampling

Soils have been tested at the plant site and numerous locations up to several miles away by agencies including Cal EPA/DTSC, Santa Cruz County with technical assistance from California Department of Public Health, CTEH working in consultation with the U.S. EPA and Monterey County, and researchers from the University of California's Agriculture and Natural Resources division.

Findings from these various efforts have been consistent in showing that (1) deposition of soot/metals potentially from the fire is localized to the immediate area of the plant and adjacent property to the north and west of the plant, and (2) levels of these metals are within normal ranges and do not pose a risk to human health or agriculture. Vistra continues to work with the U.S. EPA, Cal EPA, and others to evaluate what additional testing may be needed.

Soil investigations to date have used one or more of three testing methodologies - X-Ray Fluorescence (XRF), surface wipe sampling, and soil sampling/analysis. Both XRF and surface wipe sampling are initial screening tools used to detect metals on surfaces and to indicate where further investigation might be required. Soil sampling is the collection of soil on the surface and beneath it for further laboratory analysis and is regarded by DTSC as the most comprehensive of the three types of testing. Generally, XRF and surface wipe sampling are used first to determine where soil sampling and analysis might be required.

State of California & County Soil Testing

EPA Soot Deposition Model

This model was developed by the U.S. EPA using real-time and predictive weather modeling for three 24-hour periods plus information about the materials involved while the fire was active, to determine the area most likely impacted by the fire. This model was used to guide the surface wipe sampling work summarized below.

CTEH Surface Sampling

Summary: The surface wipe sampling data found that the only instances of surface metals above the screening levels were close to the source of the fire, as predicted by the EPA soot deposition model. Less than a month after the fire, the resampled areas found all surface metal concentrations below the screening levels, indicating that no further investigation is needed in these areas. We were not able to conduct follow-up testing at the private residence immediately north of the power plant. We are continuing to work with EPA, the County, and the State to determine what additional sampling or testing will be conducted.

Sampling: Surface wipe sampling was performed by Center for Toxicology and Environmental Health (CTEH) between January 24 and January 29, then again on February 9. Samples were tested for cobalt, manganese, and nickel, which the U.S. EPA identified as metals of potential concern for the incident. Samples were collected within the area where the EPA modeled that fire soot may have settled based on wind conditions during the event and properties of the fire, which is limited to the immediate area of the plant and adjacent property to the north and just west of the plant site.

Approved Screening Levels: Surface wipe results were compared to community outdoor surface screening levels developed using EPA methodology and approved by the California Department of Toxic Substances Control (DTSC). These health-based screening levels include a wide margin of safety to protect sensitive groups of people assuming long-term, persistent exposure. Because these screening levels are set under these conservative health-protective factors, a result above a screening level does not mean there is an immediate health concern, but rather that further investigation may be warranted.

Cobalt Sampling
Jan. 24-29

Manganese Sampling Jan. 24-29

Nickel Sampling
Jan. 24-29

Note: Results above a screening level do not mean there is an immediate health concern; they indicate that further testing may be warranted, the results of which are displayed below.

Findings: The January sampling found metals above screening levels at only the Moss Landing Power Plant property itself and at two nearby properties – one location near the Moss Landing harbor and another on a private property adjacent to the plant and to the north.

Follow-up testing on February 9 at the Moss Landing Power Plant property and near the Moss Landing harbor found that all surface metal concentrations were below the screening levels. We were not able to conduct follow-up testing at the private residence immediately north of the power plant.

Cobalt Sampling
Feb. 9

Manganese Sampling Feb. 9

Nickel Sampling
Feb. 9

Air Monitoring & Sampling

Air quality monitoring during and after the fire found no hazardous air conditions or risks to public health. These findings have been confirmed by separate monitoring performed by the U.S. EPA and the Monterey Bay Air Resources District.

As noted in modeling performed by U.S. EPA, hydrogen fluoride, a hazardous material that can be released by lithium batteries, was consumed in the fire, as noted by the U.S. EPA personnel in an incident update on January 18.  

Vistra began initial air monitoring on site at approximately 4 p.m. on Jan. 16 when the fire was first detected. The U.S. EPA arrived on site at approximately 2 a.m. on Jan. 17 and began their testing.  A leading independent environmental firm, CTEH, arrived at 5 a.m. on Jan. 17 and began conducting extensive air quality monitoring at the Moss Landing site and in the community.  CTEH mobile air monitoring personnel sampled over 100 locations, testing for seven air constituents specific to this type of fire. This was complemented by nine stationary monitoring units established by the U.S. EPA.

Out of an abundance of caution, monitoring will continue while recovery operations are underway including air sampling for metals. Air monitoring and metals sampling to date have not detected hazardous air conditions at any time, and all particulate matter readings have been within expected air quality index (AQI) bands deemed safe for the public.

Air monitoring results are shared with the U.S. EPA, Monterey County, other government agencies.

For the latest local air quality monitoring reports, visit the County of Monterey Moss Landing Response website.

Live air quality monitoring is also available on the MBARD website.

Air Quality Reports

A leading independent environmental firm, CTEH, conducted extensive air quality monitoring in and around the Moss Landing community as part of response efforts. Reports from the first week following the incident:

Water

The Marina Coast Water District issued the following statement with respect to this incident:

Marina Coast Water District (MCWD) sources its water from deep aquifers situated many miles south of Moss Landing, the site of the ongoing Moss Landing Vistra Power Plant Battery Fire. MCWD's aquifers are well-protected due to their depth and distance from the fire and are not affected by any potential contamination.

The County of Santa Cruz collected surface water and sediment samples from multiple bodies of water and confirmed that metal levels are within safe parameters and do not suggest elevated public health risks or food safety concerns.