“Because this was the first time we observed significant linked (in-school) transmission in our District, the LMSD Health Services team this week went beyond contact-tracing in an attempt to further investigate and understand conditions that could be factors in the outbreak,” the spokesperson wrote. “While the District does not have the ability to determine what strain of COVID is involved in these cases, it is able to look at other factors, such as those within the classroom.” The district’s Operations Department made a full assessment of the heating, ventilation and cooling system of the impacted room. Their inspection revealed that a manual damper within the ductwork above the ceiling was too far closed, allowing about 30% of the maximum of fresh air it should have allowed into the room.