Pollution is Cumulative and Complex

Despite all the bias baked into industry self-reported data, industry-self reported data does give a conservative picture of the extraordinary volume of pollution over time. This data is also a rare admission by the company of the extent of its pollution. 

National Pollution Release Data (NPRI) reports emissions at the Imperial Oil Refinery year to year, and chemical by chemical. This way of reporting minimizes our sense of the enormous volume of pollutants. Moreover, such data only begins in 1994, while the refinery goes back to 1871. So we only get a small snapshot of the total pollution over time.

The NPRI further minimizes pollution because the Imperial Oil complex in Sarnia reports itself as five different facilities. Thus the complex divides its pollution reporting up as another way it can minimize the sense of their responsibility for pollution. 

Below are three charts that use NPRI data give a sense of how pollution adds up over time across the Imperial Oil Sarnia complex.


Benzene is a significant concern because it is linked to blood cancers like leukemia. Imperial Oil's Sarnia Refinery is Chemical Valley's biggest benzene polluter, and consistently pollutes at high levels beyond both provincial standards and comparative US standards. Over 20 years, Imperial Oil has emitted some 500 tonnes of benzene.

Sulphur Dioxide

Sulphur Dioxide is emitted when flaring as part of the process of removing sulphur from crude oil. Sulphur Dioxide is known to cause respiratory problems as well as cardiovascular health effects. It is also linked to developmental and reproductive health issues. The Imperial Oil Refinery in Sarnia has released extraordinary levels over the last 20 years, adding up to over 200,000 tonnes.


Lead used to be an additive to gasoline. This use was banned as a gasoline additive for cars in Canada 1990. It still used in aircraft fuel. Jet fuel is a significant product of the Sarnia Imperial Oil Refinery, which supplies much of the fuel to Toronto's Pearson International Airport. Lead remains a significant pollutant. Exposure to lead can cause serious neurological effects.