An alert issued this week by INEOS Styrolution about elevated benzene levels at its Sarnia facility has since been retracted, with the company citing a “messaging system error.” A follow-up clarification was issued today, stating that no exceedances occurred on May 5.
The original message, distributed through the Sarnia-Lambton Alerts system on May 5, stated that “hourly benzene emissions on-site have been detected above 0.021 parts-per million (67.5 µg/m³).” That figure matches the company’s internal “proactive alert” threshold — a level set below Ontario’s regulatory one-hour ambient air quality criterion (AAQC) for benzene of 90 µg/m³ (approximately 0.028 ppm).
A second message, issued at 7:06 a.m. on May 7, repeated the same language from the original alert and described the notification as a “proactive precaution.” INEOS stated that emissions reduction efforts would be identified if abnormal conditions were present, and emphasized that no adverse effects were expected.
Later that same day, a correction was issued at 3:01 p.m., reading:
“CORRECTION to the notifications sent May 5th [10:53 and 11:09 a.m.]
Due to a messaging system error, two community notifications were incorrectly distributed yesterday. We would like to clarify that no on-site emissions at our Sarnia facility have exceeded 0.021 parts per million (67.5 µg/m³) on May 5, 2025.”
INEOS has not explained why the May 7, 7:06 a.m. alert repeated the exceedance language just hours before issuing the correction. As of publication, no retraction or clarification has appeared on the BASES (Binational Air Quality and Environmental Strategy) public notification platform, where the original alert was posted.
In response to questions from The Sarnia Journal, INEOS said the company uses a proactive alert threshold of 0.021 ppm to notify the public before reaching Ontario’s regulatory limit. The company confirmed that no exceedances occurred on May 5, 6, or 7 and that emissions remained below the 90 µg/m³ limit. However, it did not address questions about whether that threshold was exceeded on other dates, the cause of the messaging error, or what safeguards exist to prevent similar notification issues in the future.
OOntario’s one-hour air quality limit for benzene, the maximum amount allowed in outdoor air over a one-hour period, is 90 micrograms per cubic metre (µg/m³). INEOS’s internal alert threshold (67.5 µg/m³) represents approximately 75% of that regulatory limit and is described by the company as a proactive measure to inform the community in advance of any regulatory breach.
Benzene is a volatile organic compound used in petrochemical processing and plastics manufacturing. It is listed as toxic under the Canadian Environmental Protection Act and is classified as carcinogenic to humans by the International Agency for Research on Cancer. Long-term exposure can increase the risk of leukemia and other blood disorders, while short-term exposure to high levels may cause symptoms such as dizziness, headaches, or drowsiness.
The alerts were issued during INEOS Styrolution’s ongoing benzene removal plan at the Sarnia site, which includes pipeline transfers and the emptying of an on-site benzene tank. The company has stated that emissions controls are in place and no off-site health impacts are anticipated.
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