Vol. 149, No. 27 — July 4, 2015

Regulations Establishing a List of Spill-treating Agents (Canada Oil and Gas Operations Act)

Statutory authority

Canada Oil and Gas Operations Act

Sponsoring department

Department of the Environment


(This statement is not part of the Regulations.)


Canada has committed to modernizing its offshore oil and gas regime by implementing a world-class regulatory system and strengthening environmental protection. These Regulations support this initiative by establishing a list of spill-treating agents (STAs) acceptable for use in the event of a spill from an offshore oil facility.


Offshore oil and gas production is regulated by the Canada-Nova Scotia Offshore Petroleum Board, the Canada- Newfoundland and Labrador Offshore Petroleum Board, and the National Energy Board. These regulatory bodies ensure that operators comply with the statutory and regulatory requirements of the Canada-Nova Scotia Offshore Petroleum Resources Accord Implementation Act, the Canada–Newfoundland Atlantic Accord Implementation Act and the Canada Oil and Gas Operations Act (COGOA), respectively, for the purpose of preventing spills in Canada’s offshore.

Spill-treating agents are substances that can be applied following an oil spill to help control the path the spill takes and to mitigate the effects of the spill on the environment. “Spill-treating agent” is a generic term that includes dispersants, herding agents, emulsion treating agents, solidifiers, bioremediation agents, and surface-washing agents. The deposit of deleterious STAs into Canadian waters is potentially prohibited under a number of federal environmental statutes, including the Migratory Birds Convention Act, 1994, the Fisheries Act and the ocean disposal provisions of the Canadian Environmental Protection Act, 1999 (CEPA 1999).

The Energy Safety and Security Act, which received royal assent on February 26, 2015, aims to strengthen the safety and security of offshore oil production through improved oil spill prevention, response, accountability and transparency. The Act amends the Canada-Nova Scotia Offshore Petroleum Resources Accord Implementation Act, the Canada–Newfoundland Atlantic Accord Implementation Act and the COGOA to allow for the use of STAs in the offshore under five conditions. Specifically, in the event of an oil spill, the Act lifts the legal prohibitions that would otherwise prevent the use of an STA, provided that

In addition, in the event of a spill after the new legislative regime is in force (in the transition period during which conditions of use regulations will be under development), the regulator of the offshore facility responsible for the spill must consult the Minister for scientific advice on spill response, including the determination of net environmental benefit. Environment Canada data from STA testing will be available to assist in the determination of net environmental benefit.

For the purpose of this regime, section 14.2 of the COGOA authorizes the Minister of the Environment to make ministerial regulations establishing a list of STAs that are acceptable for use in Canada’s offshore. The Minister of the Environment will also work with the ministers of Natural Resources and Indian Affairs and Northern Development to develop another set of regulations defining in greater detail the conditions of use of STAs within five years of the Act receiving royal assent.


The Minister of the Environment has determined that the STA products listed in the proposed Regulations are acceptable for use in Canada’s offshore. As a result, upon the coming into force of the Regulations, the appropriate regulatory body (the offshore boards) will be able to authorize the use of one or more of the STA products listed in the proposed Regulations under the conditions described above to respond to an oil spill.


Approach for the selection of products for inclusion on the list

The objective of the evaluations was to assess classes of STAs and identify those products that are known in the spill response community to offer high efficacy and low toxicity. The evaluations considered real documented spill experience and scientific studies by Environment Canada, other government departments and international agencies, academia and industry.

The STAs recommended for inclusion on this list have been studied over a period of decades under a variety of conditions and test methods to evaluate the functionality of STAs for use on oil spills and to develop test methods for comparing the relative effectiveness of products within an STA class. The recommended products have consistently demonstrated best-in-class performance and are typically selected as the representative product within their respective class of STA by oil spill researchers throughout Canada and the United States. Environment Canada also considered the results of laboratory test methods used in other jurisdictions and tests related to different conditions of use (temperature, dose rate, or water salinity) or variation in oil type or scale (using wave tanks and test basins) to validate its conclusions. Finally, the evaluation also considered documented experiences from field studies and actual spill response activities.

Ecological risk from STA use was assessed using a set of acute toxicity reference methods developed by Environment Canada, as well as a comparison of the product ingredients to Schedule 1 of CEPA 1999 (the List of Toxic Substances) to identify potential components of concern. Given the potential for products to be used during offshore, cross-border oil spill incidents, the National Oil and Hazardous Substances Pollution Contingency Plan (NCP) of the U.S. Environmental Protection Agency (U.S. EPA) was also reviewed to determine the compatibility of the listed products between Canada and the United States.

Environment Canada STA test criteria and test methods

The scientific testing conducted by Environment Canada to identify the STAs listed in the proposed Regulations focused on assessing toxicity and effectiveness.

Toxicity is the inherent potential or capacity for a material or substance to cause an adverse effect on a group of selected organisms of a single species under defined conditions. Acute toxicity refers to adverse effects resulting from a single exposure to a substance or material, or from multiple exposures in a short period of time. In examining acute toxicity, scientists consider lethal as well as sublethal effects, that is, changes related to physiological processes, growth, reproduction, behaviour and development as a result of exposure to the substance or material. An acute aquatic toxicity test typically measures either the proportion of organisms affected, or the degree of effect shown, after exposure to a specific test material or substance. Since no single test method or test organism can be expected to comprehensively represent all environmental impacts, scientists perform a combination of toxicity tests on different types of organisms to assess toxicity.

The use of STAs will generally only result in acute exposure to affected species. To assess the acute toxicity of STA products, Environment Canada scientists use the following standard Canadian reference methods targeting a range of species:

These reference methods are used by laboratories that are accredited by the Standards Council of Canada or the Canadian Analytical Laboratories Association, according to International Organization for Standardization (ISO/IEC 17025:2005 available at http://www.iso.org/iso/catalogue_detail.htm?csnumber=39883) requirements aimed at ensuring that the laboratories are technically and scientifically competent and that test results are reliable.

Recognizing that the reference methods traditionally used to determine the deleteriousness of the product may not be best suited to the marine context, Environment Canada is taking steps to evaluate the applicability of alternative reference methods using relevant Canadian marine species, with species sensitivity being a major consideration. In addition, the scientific literature has been consulted to understand the current state of knowledge for laboratory and real world use. The U.S. EPA has done extensive work on dispersant toxicity both with and without oil, including endocrine disruption.

Effectiveness measures depend on the class of STA. An effective dispersant is one that rapidly and comprehensively transfers oil from a slick at the surface down into the water column as small droplets. An effective washing agent enhances the removal of oil adhering to hard surfaces such as rocky shorelines and human-made structures.

Dispersant effectiveness varies depending on several factors, including oil type, oil-weathering state, sea energy, salinity and temperature, and dispersant dose. A standard test is necessary to establish a baseline performance parameter so that dispersant products can be compared. However, laboratory test results cannot be considered an absolute measure of performance at sea where spill and sea conditions will vary; they must be supplemented with evidence from actual oil spill responses.

Environment Canada uses the following tests to evaluate dispersant effectiveness:

Environment Canada developed the “Inclined Trough Test” (ITT) to determine the effectiveness of surface-washing agents. This test measures the ability of a product to move oil away from a test surface. Specifically, a bead of oil is applied at the crease of a stainless steel trough and treated with a surface-washing agent, then flushed with water. The cleaning effectiveness of the surface-washing agent is determined by measuring the difference in weight of the oil before and after treatment. The U.S. EPA has identified the ITT for effectiveness testing under proposed changes to its National Contingency Plan. Efforts are underway at Environment Canada to develop an improved effectiveness test using natural substrates.

Environment Canada’s approach to evaluating STAs is consistent with those of other jurisdictions, notably the U.S. EPA. Like Environment Canada, the U.S. EPA examines the toxicity and effectiveness of STAs. (see footnote 2) With respect to toxicity, the U.S. EPA considers acute toxicity, but does not currently measure sublethal effects. Its approach may be broadened in the future to be made more similar to Canada’s approach by adding consideration of acute sublethal effects. The U.S. EPA is also assessing chronic effects based on experience gained through the Deepwater Horizon incident. (see footnote 3) The tests used by the U.S. EPA to measure acute toxicity are similar to those used by Environment Canada, with differences related to the target test species. Environment Canada has evaluated the acute lethality of the STAs listed in the proposed Regulations on three common aquatic test species: a vertebrate (fish), an invertebrate (water flea), and a bacterium. The U.S. EPA currently evaluates the acute lethality of the STA alone and in combination with fuel oil on two marine species: a vertebrate (fish) and an invertebrate (shrimp).

With regard to dispersant effectiveness, the U.S. EPA uses a modified swirling flask test. The U.S. EPA recently indicated that it is considering changing its approach to use the baffled flask test. (see footnote 4) Environment Canada uses both tests. As noted above, Environment Canada uses its ITT to measure the effectiveness of surface-washing agents. While the U.S. EPA does not currently measure the effectiveness of surface-washing agents, it has proposed use of the ITT. (see footnote 5)

Proposed STA products for listing

For these Regulations, Environment Canada scientists have conducted scientific evaluations and have identified two products (one dispersant and one surface-washing agent) known to offer best-in-class characteristics based on extensive long-term study, and demonstrated success during actual oil spill responses in other jurisdictions. The evaluations concluded that these products possess favourable characteristics as oil spill countermeasures and offer the potential for high efficacy coupled with limited toxicity to biota in the marine environment. The Minister of the Environment therefore proposes that these STAs be included in the Regulations:

1. Corexit® EC9500A

This dispersant has been the subject of considerable domestic and international study in the laboratory, in test tanks, and in response to spill emergencies such as the Deepwater Horizon well blowout in 2010. It has been available in the global marketplace for many years and is authorized for use in a number of countries. It is listed for possible use in the United States.

Test results

Corexit® EC9500A is highly effective in laboratory performance screening tests and was determined to be “practically non-toxic” (see footnote 6) by international standards in aquatic toxicity tests. The individual ingredients are not found on Schedule 1 of CEPA 1999.

2. Corexit® EC9580A

This surface-washing agent is suitable as a hard-surface cleaner on shorelines and man-made structures. It has been the subject of considerable study in the laboratory, in field trials, and in response to spill emergencies such as the Morris J. Berman spill in 1994 in Puerto Rico. It has been available in the global marketplace for many years and is listed for possible use in the United States.

Test results

Corexit® EC9580A is highly effective in laboratory performance screening tests and was determined to be “non-toxic” (see footnote 7) by international standards in aquatic toxicity tests. The individual ingredients are not found on Schedule 1 of CEPA 1999.

Amendments to the list of spill-treating agents

The Minister of the Environment may amend these Regulations by adding other STAs in the future. Other STA products will be tested for toxicity and effectiveness on the basis of criteria to be established relative to the best-in-class products. Environment Canada will also evaluate data available from other sources, such as the U.S. EPA’s NCP. Should new information become available that indicates a listed product poses a greater risk to the environment than originally estimated, the product can be removed from the list.

In evaluating other STA products for possible addition to this regulatory list, Environment Canada may also conduct supplemental studies as warranted to ascertain the risks and the potential ecological impacts related to product use, such as amendment of oil mobility that may affect the fate and transport of the treated oil, and the toxicity of degradation by-products. A significant weight will be given to lessons learned from experience gained during actual spill response, as available.

“One-for-One” Rule and small business lens

This proposed regulation will not impose administrative or compliance burden on business; therefore, neither the small business lens nor the “One-for-One” Rule apply to the proposed Regulations.


Federal departments and partners have been consulted through existing mechanisms, including the Frontier and Offshore Regulatory Renewal Initiative Steering Committee.


The proposed Regulations establishing a list of STAs fulfills the definition of a “spill-treating agent” as contemplated in the Energy Safety and Security Act. There are no other alternatives to regulation.

In order to enable the spill response regime that has been enhanced by the permissible use of STAs, the provisions of the Energy Safety and Security Act must come into force. Unless brought into force by order of the Governor in Council, the relevant legislative provisions will come into force no later than 12 months after royal assent of the Act.


Dr. Carl Brown
Emergencies Science and Technology Section
Science and Technology Branch
Environment Canada
335 River Road
Ottawa, Ontario
K1V 1C7
Email: ESTD.INFO@ec.gc.ca


Notice is given that the Minister of the Environment, pursuant to section 14.2 (see footnote a) of the Canada Oil and Gas Operations Act (see footnote b), proposes to make the annexed Regulations Establishing a List of Spill- treating Agents (Canada Oil and Gas Operations Act).

Interested persons may make representations concerning the proposed Regulations within 30 days after the date of publication of this notice. All such representations must cite the Canada Gazette, Part I, and the date of publication of this notice, and be addressed to Carl E. Brown, Manager, Emergencies Science and Technology Section, Environment Canada, 335 River Road, Ottawa, Ontario K1V 1C7 (email: ESTD.INFO@ec.gc.ca).

Ottawa, June 22, 2015

Minister of the Environment



1. The list set out in the schedule is established for the purposes of the definition “spill-treating agent” in section 2 of the Canada Oil and Gas Operations Act.

Coming into force

2. These Regulations come into force on the day on which they are registered.

(Section 1)


  1. Corexit® EC9500A
  2. Corexit® EC9580A