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  • Interstate 10 incident: public health information

    Updated February 15, 2023

    The Pima County Health Department working with the Arizona Poison and Drug Information Center have released the following guidance for any person who believes they may have been exposed to the toxic fumes associated with a hazardous materials spill on Interstate 10 Feb. 14. 
    The hazmat incident is ongoing as state and local emergency response agencies work to clean up the spill and remediate the accident scene. 
    The spill involved nitric acid. Concentrated nitric acid is also called fuming red nitric acid and releases a gas, nitrogen dioxide. Nitrogen dioxide is a slightly irritant gas that with prolonged exposure especially in a confined space with the source of nitrogen dioxide, can cause delayed lung complications up to 24 hours after exposure. 
    Pima County Health Department and Poison Control are recommending that individuals who may have been in contact with the gas for more than 15 minutes assess themselves for exposure risk.


    If an individual has met that 15 minute or more exposure within a mile of the incident and developed respiratory difficulties or new symptoms (wheezing, shortness of breath; difficulty breathing, exacerbations of COPD or asthma) they should seek medical evaluation. It is possible that individuals who lived within a mile of the exposure and sheltered in place but were using air exchange that pulled air from the outside may have met this threshold. 
    People who drove through or past the accident and chemical plume should not have met this threshold.

    If exposed, people may have delayed onset of symptoms, up to 12-24 hours later.  
    Any respiratory difficulties or symptoms (wheezing, shortness of breath) should be evaluated promptly by your doctor, or at an urgent care center or emergency room.


    Should outdoor objects such as lawn furniture, playground equipment and the like be wiped down?

    Concentrations in the immediate area of the spill are low or undetectable. Contamination of objects that were left outdoors is unlikely. Specific recommendations are as below:

    • Indoors within the one-mile zone: no need to clean anything, including HVAC systems.

    • Outdoor equipment within the one-mile zone: wipe down with water.
    For up to date information about the accident and its status overall, go to the Arizona Department of Public Safety’s Information Page.

    Are you concerned that you make have been exposed to fumes associated with this incident? This secure, confidential survey can help you figure out next steps.
    The Health Department has distributed this guidance to state medical providers to assist them if receive patients who may be suffering from inhalation injuries associated with Tuesday's chemical spill. 

    HazMat Spill Clinical Guidance 
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