What is the appropriate first step if a hazardous material release occurs in an area?

When a hazardous material release occurs, a crucial first step is to close doors and windows and shut off HVAC units. This action helps to minimize the infiltration of hazardous materials into the building and limits the spread of contaminants. By effectively sealing off the area, responders can prevent further exposure to airborne toxins and reduce the risk to individuals within the vicinity.

In addition, shutting down HVAC systems is essential since these systems can distribute hazardous materials throughout the building, leading to wider contamination. By ensuring that the area remains contained, responders can help maintain a safer environment for those who may need to address the situation.

While other choices may seem reasonable in certain contexts, they do not prioritize safety effectively. For instance, opening windows for ventilation could inadvertently allow more contaminants to enter the structure, while immediate evacuation without securing the area could expose individuals to hazardous substances. Finally, contacting emergency services is necessary, but it should follow taking initial protective measures to safeguard individuals from immediate dangers.