Many of the 189 hazardous air pollutants (HAPs) listed in the Environmental Protection Agency regulations can be monitored by frequency agile CO2 DIAL (FACD) systems. These systems can be used to survey industrial and military installations and toxic waste repositories at ranges of a few kilometers from emission sources. FACD systems may become a valuable tool for detection and estimation of a wide array of HAPs. However, in most cases, several of the listed HAPs will be present simultaneously and discrimination of one HAP from another based on differences in spectral characteristics can be challenging for FACD systems. While FACD hardware is mature and is capable of addressing these discrimination issues, multiple-contaminate separation algorithms need to be developed. A one week field test was conducted at Los Banos, California, to gather multiple HAP data that will be used for future algorithm development. A vapor chamber was used to control disseminated concentrations of each HAP and reduce effects of atmospheric turbulence and wind direction and speed. Data was collected for several chemicals injected into the vapor chamber simultaneously. The data and results from the field test are presented and calibration issues are discussed.