
Benzene Fenceline Monitoring Program
Shell Norco conducts biweekly passive sampling along the facility property boundary for the target analyte of benzene. The passive samples are collected and analyzed in accordance with Methods 325A and 325B of Appendix A to 40 CFR Part 63.
How the Program Works
Shell Norco implements the Benzene Fenceline Monitoring Program by utilizing passive absorption sampling, a process in which clean absorbent tubes are deployed and collected every two weeks and sent to a laboratory for concentration analysis. When used tubes are collected, a new set of tubes is immediately deployed to begin the next two-week sampling period.
From these sampling results, a period benzene concentration delta (Δc) is calculated using the minimum and maximum individual monitor results. An annual rolling average using 26 period ΔC’s is also calculated and compared against the action level of 9 µg/m3. Within 5 days of determining that the action level has been exceeded for any annual average Δc and no longer than 50 days after completion of the sampling period, Shell Norco will initiate a root cause analysis (RCA). Once corrective actions are implemented, if the next period following implementation is also above the action level, Shell Norco will develop a corrective action plan and submit to the USEPA within 60 days.
Public Communications
As part of this program, Shell Norco will post the individual sample result for each monitor, each biweekly annual average concentration difference value, as well as any corrective action plans submitted to the USEPA. The sample results will be posted within 30 days of the end of the biweekly sampling period and can be found in the database below.

Archived Reports
- Report from 10-09-25 (PDF, 183 kB)
- Report from 08-27-25 (PDF, 183 kB)
- Report from 08-13-25 (PDF, 183 kB)
- Report from 07-30-25 (PDF, 183 kB)
- Report from 07-16-25 (PDF, 183 kB)
- Report from 07-02-25 (PDF, 183 kB)
- Report from 06-18-25 (PDF, 145 kB)
- Report from 06-04-25 (PDF, 143 kB)
- Report from 05-21-25 (PDF, 140 kB)
- Report from 05-07-25 (PDF, 140 kB)
- Report from 04-23-25 (PDF, 143 kB)
- Report from 04-09-25 (PDF, 143 kB)
- Report from 03-26-25 (PDF, 160 kB)
- Report from 03-12-25 (PDF, 176 kB)
- Report from 02-26-25 (PDF, 176 kB)
- Report from 02-12-25 (PDF, 326 kB)
- Report from 01-29-25 (PDF, 176 kB)
- Report from 01-15-25 (PDF, 176 kB)
- Report from 31-12-24 (PDF, 176 kB)
- Report from 12-18-24 (PDF, 176 kB)
- Report from 12-04-24 (PDF, 176 kB)
- Report from 11-20-24 (PDF, 176 kB)
- Report from 11-06-24 (PDF, 176 kB)
- Report from 10-23-24 (PDF, 176 kB)
- Report from 10-09-24 (PDF, 176 kB)
- Report from 09-25-24 (PDF, 176 kB)
- Report from 09-10-24 (PDF, 176 kB)
- Report from 08-28-24 (PDF, 160 kB)
- Report from 08-14-24 (PDF, 160 kB)
- Report from 07-31-24 (PDF, 176 kB)
- Report from 07-17-24 (PDF, 176 kB)
- Report from 06-19-24 (PDF, 176 kB)
- Report from 07-03-24 (PDF, 176 kB)
- Report from 06-05-24 (PDF, 176 kB)
- Report from 05-22-24 (PDF, 176 kB)
- Report from 05-08-24 (PDF, 176 kB)
- Report from 04-24-24 (PDF, 176 kB)
- Report from 04-10-24 (PDF, 76 kB)
- Report from 03-27-24 (PDF, 176 kB)
- Report from 03-13-24 (PDF, 176 kB)
- Report from 02-28-24 (PDF, 177 kB)
- Report from 02-14-24 (PDF, 176 kB)
- Report from 01-31-24 (PDF, 176 kB)
- Report from 01-17-24 (PDF, 176 kB)
- Report from 01-03-24 (PDF, 176 kB)
- Report from 12-20-23 (PDF, 76 kB)
- Report from 12-06-23 (PDF, 76 kB)
- Report from 11-22-23 (PDF, 177 kB)
- Report from 11-08-23 (PDF, 177 kB)
- Report from 10-25-23 (PDF, 76 kB)
- Report from 10-11-23 (PDF, 94 kB)
- Report from 09-27-23 (PDF, 94 kB)
- Report from 09-13-23 (PDF, 94 kB)
- Report from 08-30-23 (PDF, 94 kB)
- Report from 08-16-23 (PDF, 94 kB)
- Report from 08-02-23 (PDF, 94 kB)
- Report from 07-19-23 (PDF, 78 kB)
- Report from 07-05-23 (PDF, 94 kB)
- Report from 06-21-23 (PDF, 94 kB)
- Report from 06-07-23 (PDF, 94 kB)
- Report from 05-24-23 (PDF, 78 kB)
- Report from 05-10-23 (PDF, 94 kB)
- Report from 04-26-23 (PDF, 94 kB)
- Report from 04-12-23 (PDF, 94 kB)
- Report from 03-29-23 (PDF, 94 kB)
- Report from 03-15-23 (PDF, 94 kB)
- Report from 03-01-23 (PDF, 94 kB)
- Report from 02-15-23 (PDF, 94 kB)
- Report from 02-01-23 (PDF, 94 kB)
- Report from 01-18-23 (PDF, 78 kB)
- Report from 01-04-23 (PDF, 94 kB)
- Report from 12-21-22 (PDF, 94 kB)
- Report from 12-07-22 (PDF, 94 kB)
- Report from 11-23-22 (PDF, 94 kB)
- Report from 11-09-22 (PDF, 94 kB)
- CAP 08-17-22 to 10-12-22 (PDF, 7 MB)
- Report from 10-26-22 (PDF, 94 kB)
- Report from 10-12-22 (PDF, 94 kB)
- Report from 09-28-22 (PDF, 94 kB)
- Report from 09-14-22 (PDF, 94 kB)
- Report from 08-31-22 (PDF, 94 kB)
- Report from 08-17-22 (PDF, 78 kB)
- Report from 08-03-22 (PDF, 78 kB)
- Report from 07-20-22 (PDF, 94 kB)
- Report from 07-07-22 (PDF, 94 kB)
- Report from 06-23-22 (PDF, 94 kB)
- Report from 06-09-22 (PDF, 94 kB)
- Report from 05-26-22 (PDF, 94 kB)
- Report from 05-12-22 (PDF, 94 kB)
- Report from 04-28-22 (PDF, 7 MB)
- Report from 04-14-22 (PDF, 94 kB)
- Report from 03-31-22 (PDF, 94 kB)
- Report from 03-17-22 (PDF, 94 kB)
- Report from 03-03-22 (PDF, 94 kB)
- Report from 02-17-22 (PDF, 106 kB)
- Report from 02-03-22 (PDF, 52 kB)
- CAP 10-21-21 to 11-04-21 (PDF, 8 MB)
- Report from 01-19-22 (PDF, 52 kB)
- Report from 01-05-22 (PDF, 52 kB)
- Report from 12-21-21 (PDF, 52 kB)
- Report from 12-07-21 (PDF, 52 kB)
- Report from 11-18-21 (PDF, 52 kB)
- Report from 11-04-21 (PDF, 95 kB)
- Report from 10-21-21 (PDF, 95 kB)
- Report from 10-07-21 (PDF, 95 kB)
- Report from 09-23-21 (PDF, 95 kB)
- CAP 07-15-21 to 07-29-21 (PDF, 4 MB)
- Report from 09-09-21 (PDF, 95 kB)
- Report from 08-26-21 (PDF, 95 kB)
- Report from 08-12-21 (PDF, 95 kB)
- Report from 07-29-21 (PDF, 95 kB)
- CAP 05-20-21 to 06-03-21 (PDF, 961 kB)
- Report from 07-15-21 (PDF, 95 kB)
- CAP 03-26-21 to 04-09-21 (PDF, 6 MB)
- Report from 07-01-21 (PDF, 95 kB)
- Report from 06-17-21 (PDF, 95 kB)
- Report from 06-03-21 (PDF, 95 kB)
- Report from 05-20-21 (PDF, 95 kB)
- Report from 05-06-21 (PDF, 95 kB)
- Report from 04-22-21 (PDF, 94 kB)
- Report from 04-09-21 (PDF, 148 kB)
- Report from 03-26-21 (PDF, 271 kB)
- Report from 03-12-21 (PDF, 271 kB)
- Report from 02-25-21 (PDF, 271 kB)
- Report from 02-10-21 (PDF, 271 kB)
- Report from 01-28-21 (PDF, 271 kB)