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Colorado to Issue New General Permit for Stormwater Discharges Associated with Non-extractive Industrial Activity

Posted: May 31st, 2022

Authors: Adam C. 

The Colorado Department of Public Health and Environment’s (CDPHE) Discharge Permit System (CDPS) has issued Draft General Permit COR900000 for Stormwater Discharges Associated with Non-extractive Industrial Activity (permit). The permit is currently in a public comment period that is set to end on June 13, 2022. The last COR900000 permit’s expiration date was June 30, 2017, but it was administratively extended.

The draft permit includes a few new topics. The first is lower benchmark monitoring concentrations for several parameters, mostly metals. Benchmark monitoring involves the sampling of stormwater runoff and is required for some industrial sectors. A facility’s sector is determined by its Standard Industrial Classification (SIC) code. The benchmark analytical data help characterize the quality of facility discharges and are compared to values listed in the permit to evaluate the effectiveness of storm water management controls.

Additional Implementation Measures (AIM) have also been added to the draft permit. These are basic control measures that must be implemented if certain trigger conditions are met (such as a benchmark monitoring exceedance or an unauthorized release or discharge). There are three AIM levels. A facility starts at baseline, and a trigger condition will cause the facility to proceed to AIM Level 1. A facility may return to baseline status if required control changes have been made and the average of the next four quarterly benchmark monitoring results for the contaminant-of-concern is below the benchmark concentration. A successive trigger condition will move the facility into the next AIM level. More stringent storm water management controls must be implemented at each higher AIM level.

The draft permit will not allow per- and polyfluoroalkyl substances (PFAS) in facility discharges. PFAS are chemicals used in fire-fighting foam (e.g., aqueous film forming foam, or AFFF), food packaging, carpet, and non-stick products. They can cause adverse health issues and are persistent in the environment. Benchmark monitoring for PFAS will be required for certain sectors (e.g., Sector S – Air Transportation, SIC code 45). Target concentrations have not been included, but in 2016 the United States Environmental Protection Agency (U.S. EPA) issued a health advisory level of 70 ng/L for the sum of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in drinking water.

Another addition to the draft permit that has the potential to impact the regulated community involves coal tar. Areas where coal tar sealant has been applied (after the pending effective date of the permit) will not be eligible for permit coverage due to high levels of polycyclic aromatic hydrocarbons (PAH) associated with coal tar. Several PAH are known carcinogens. Coal tar sealant is typically used to coat asphalt surfaces. Existing coal tar coatings must be documented in a facility’s (required) annual reports. Alternatives could be to remove the coal tar or obtain a National Pollutant Discharge Elimination System Individual permit.

Once the permit is issued, those seeking coverage under it will have to apply via Colorado Environmental Online Services (CEOS). A facility must have a Stormwater Management Plan (SWMP) in place before applying. CDPHE normally mails existing permit holders a letter to inform them when it is time to re-apply. The typical time allowed for re-application is 90 days.

ALL4 is available to assist with your permitting or compliance needs. If you have questions about how the draft permit could affect your facility, please reach out to Adam Czaplinski at aczaplinski@all4inc.com.


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