Continuous Emissions Monitoring System (CEMS)

A Continuous Emission Monitoring System, or CEMS, utilizes devices that continuously measure the exhaust gases for certain pollutants recorded on a 1-minute basis. To ensure they are operating properly, the CEMS are subject to a variety of quality assurance tests, including regular calibration and performance testing.

All of our facilities measure sulfur dioxide, nitrogen oxides, carbon monoxide and opacity, in addition to other parameters that vary by state. Our operating permits, issued by state environmental agencies under authority from the US Environmental Protection Agency (US EPA), tell us what we need to measure.

The data from the CEMS allows for comparison of our performance against US EPA and state emission limits. Our operators also use the data to monitor facility processes, including air pollution control equipment, and to make adjustments as needed to ensure proper operation and compliance.

Making this information available to our community members is not a regulatory or permit requirement. Reworld™ posts this data in order to be transparent with the public, environmental agencies and our clients regarding our environmental performance. Note that not all facilities have their data posted as of yet, but we are working to have them all online in the near future.

By making this data publicly accessible, it is our hope that people will see beyond the industrial exteriors of our facilities and have an opportunity to engage with the work we are doing on behalf of the environment, and at the same time, develop a greater appreciation for the essential role our dedicated employees play in safely and sustainably managing the waste society creates.

CEMS data is used to determine if our emissions comply with the limits contained in our permits. Additional emissions data is gathered during semi-annual or annual stack testing using approved testing protocols. Compliance with these emission limits is reported to US EPA and state environmental agencies.

Yes, the CEMS data that is posted is the same data used for reporting to federal and state agencies on a quarterly, semi-annual and annual basis.

Our facility operators must quickly act to address emissions that are above the limit, including shutting down the unit, if required. Emissions that are over a limit are reported to the state environmental agency (reporting requirements will vary from state-to-state). As a general rule, we are in compliance with our continuous emission limits well over 99% of the time.

First, some of our permit requirements are established on a daily basis, so we need to wait until the day is complete before we can calculate the average, or in some cases, the maximum results for the day. Second, our facility personnel verify that the data meets all quality assurance requirements for regulatory and reporting purposes. Factors such as monitor downtime, required calibrations and/or use of a backup monitor may require that we confirm the data to ensure that it is accurate and meets environmental reporting requirements. However, all data that meets these requirements, even if it shows our units out of compliance, will be posted.