Fenceline monitoring is the use of monitoring technology to measure the ambient air concentration at the property line or perimeter of a manufacturing site (e.g., petroleum refinery, chemical plant) for a specific chemical. A work practice standard for fenceline monitoring was published by the United States Environmental Protection Agency ("US EPA") as an appropriate method to provide open and transparent evaluation of a site’s emissions monitoring and control methods on an on-going basis.
To achieve that goal, US EPA developed a work practice and published it in December 2015. This work practice specified the monitoring technology to be used, an implementation approach, and a benzene fenceline concentration action level above which owners or operators would be required to implement corrective action to reduce their fenceline concentration to below this action level. The details of the fenceline monitoring work practice is prescribed in EPA Test Methods 325A and 325B.
This is the work practice that Dow is using for our fenceline monitoring program.
Fenceline (or perimeter) monitoring is the use of monitoring technology to measure the ambient air concentration of a specific chemical at the property line of a manufacturing site (e.g., petroleum refinery, chemical plant).
The air samples are collected by tubes, which are filled with a sorbent material to collect any trace levels of benzene that are in the atmosphere. Multiple tubes are placed around the fenceline of the facility at a height of 5 to 10 feet above grade and uncapped to expose them to air. After two weeks, the tubes are recapped and sent to an independent accredited laboratory for analysis.