In a recent Risk and Technology Review (RTR) for the ferroalloy industry, the US EPA introduced a provision requiring the use of the digital camera opacity technique (DCOT), in accordance with American Society for Testing and Materials (ASTM) standard D7520-13.  The DCOT would have replaced the current rule requirement to conduct EPA Method 9 opacity observations, which involves visual observations and documentation by a certified Method 9 person.  Currently, there exists only one manufacturer for the DCOT, raising questions of price surges and shortage of equipment.  Additionally, as with all technology, there are concerns regarding equipment accuracy, higher costs, increased processing time, and restrictions on equipment usage in certain scenarios.  On the other hand, the DCOT offers better documentation, objective measurement, and less frequent training requirements.  The Virginia Department of Environmental Quality (VDEQ) performed a field evaluation on the Digital Compliance Opacity System II (DOCS II) and the results of the analysis can be found here.  Industries are concerned that the use of DCOT for the ferroalloy industry would set a precedent for other industries as well and have submitted a large amount of comments to the US EPA regarding this technology.  As a result, the US EPA has initiated a reconsideration for the final ferroalloy industry rule to obtain more comments regarding this technology.