Without deciding between CalOSHA’s two tests for employer liability for harmfully exposing employees to atmospheric contaminant–i.e., the “harmful exposure” standard which requires proof of exposure to airborne contaminant that actually result in or have a probability of resulting in illness, or the “zone of danger” standard (i.e., that it is reasonably predictable by operational necessity or otherwise, including inadvertence, that employees have been, are, or will be in the zone of danger)–this decision holds that CalOSHA failed to show that Granite harmfully exposed its construction workers to the fungus that causes Valley fever. There was no evidence to show that the fungus was present in the soil at the work site. While the fungus is endemic in California, it is not present everywhere in the state, and CalOSHA did not present evidence to show it was present at the work site. So, it also failed to show there was an actual zone of danger at that site. However, the decision holds there was sufficient evidence to support CalOSHA’s citation for the employer’s requiring workers to wear respirators without first providing a medical evaluation to determine the employee’s ability to use a respirator. Granite claimed it had workers sign statements that the masks it provided were for voluntary use, but there was sufficient evidence to show that supervisors told workers to wear the masks.