This document discusses determining environmental assessment levels (EALs) for amines and their degradation by-products from carbon capture and storage plants. It notes there are known knowns, known unknowns, and unknown unknowns when it comes to the toxicity of these chemicals. 15 chemicals are identified for establishing EALs, including primary, secondary, and tertiary amines and nitrosamines. A five-step process is outlined to collate hazard data, score chemicals according to toxicity criteria, and conduct toxicological reviews to ultimately rank the chemicals and determine sufficient data for setting EALs. Read-across methods are discussed as a tool to establish EALs for chemicals lacking data. The next steps include finalizing EAL

1. Determining Environmental
Assessment Levels (EALs) for
amines and degradation by-products
-
And the poetic assertions of Donald Rumsfeld
Rick Gould and David Howard
Environment Agency
September 2023

2. The known and unknown
2
“There are known knowns,
These are the things we know we know.
We also know there are known unknowns.
That is to say, we know there are some things
we do not know.
But there are also unknown unknowns.
The ones we don’t know we don’t know.”

3. What we know
3
• More than one type of
carbon-capture plant
• Amine-based solvent-
capture most common
• Emissions of amines and
degradation by-products
• Nitramines and
nitrosamines
• Varying degrees of
toxicity
• Need to assess and
reduce risks

4. Over a decade of global research
4

5. Amine degradation by-products
5
1. Reactions believed to occur predominantly in the atmosphere
2. CERC ADMS-Amines Module

6. Known unknowns
6
• Regulatory – relatively new process, permitting beginning
• Environmental assessment levels (EALs) unavailable for
most amines and by-products
• Currently only EALs for ethanolamine (MEA) and N-
Nitrosodimethylamine (NDMA)
• Little or no toxicity data for many compounds
• Industrial reluctance to sharing data on amine-based
solvents
• Commercial confidentiality - proprietary solvents
• Need for environmental-risk factors
• Environmental Assessment Levels (EALs for modelling)
• Measurement methods

7. Regulatory loop
7

8. Target chemicals for EALs
8
Primary
amines
Secondary
amines
Tertiary
amines
Nitramines Nitrosamines
Team: Ricardo, UKHSA, Environment Agency, plus CCSA, other stakeholders

9. Five-step process
9
Step 1
Collating the original list of chemicals
• Harmonised/notified
classifications
• Structural alerts
• Mutagenic,
carcinogenic, skin
sensitisation
Step 2
Collating hazard data
Step 5
Overall ranking
Step 4
Scoring - toxicological reviews
Step 3
Scoring chemicals according to hazard

10. • 40 substances
• Included intermediaries and breakdown
products
Collate the list of chemicals
Harmonised classifications
(for relevant hazard codes relating
to inhalation)
Group 1 16 chemicals
Notified classifications
(for relevant hazard codes relating
to inhalation)
Group 2 14 chemicals
No classifications / no database
entry (ECHA)
Group 3 10 chemicals
ECHA: The European Chemicals Agency

11. Hazard criteria
11
Eye
irritation
Acute
inhalation
Sensitising
Skin, respiratory
Organ
toxicity
(Acute)
CMR
Carcinogenic,
mutagenic,
reproductive
Organ
toxicity
(Chronic)

12. Data and methodologies
12
Databases • Agency for Toxic Substances and
Disease Registry (ATSDR)
• Organisation for Economic Co-
operation and Development
(OECD) Chemicals Database
• European Chemicals Agency
(ECHA)
• OECD
Methodologies • Cramer Classification (Low,
Medium, High)
• Simplified Molecular-Input Line-
Entry System (SMILES)
• ECHA Read Across Assessment
Framework (RAAF)
Tools Toxtree – Open Source software for
structural alerts

13. Toxtree
13
Source: https://toxtree.sourceforge.net/
Toxic hazard
estimation by a
decision-tree
approach

14. The fifteen compounds
14
Primary amines
2-amino-2-methyl-propanol
Secondary amines
Dimethylamine
Diethylamine
Piperazine
Diethanolamine
Morpholine
Tertiary amines
2-(diethylamino)ethanol
N-Methyldiethanolamine
Nitramines
N-nitrodiethanolamine
Diethylnitramine
Dimethylnitramine
N-nitromorpholine
2-methyl-2-(nitroamino)-1-propanol
Nitrosamines
N-nitrosopiperazine
N-nitrosomorpholine

15. From data to EALs
15
Sufficient data for EALs
Primary amines
2-amino-2-methyl-propanol
Secondary amines
Dimethylamine
Diethylamine
Piperazine
Diethanolamine
Morpholine
Tertiary amines
2-(diethylamino)ethanol
Nitrosamines
N-nitrosomorpholine
Insufficient or no data for EALs
Nitramines
N-Methyldiethanolamine
N-nitrodiethanolamine
Diethylnitramine
Dimethylnitramine
N-nitromorpholine
2-methyl-2-(nitroamino)-1-propanol
Nitrosamines
N-nitrosopiperazine

16. ECHA Read Across Assessment Framework
16

17. Read-across methods
17
Physical
Analogues:
e.g. NDMA
Chemical
Toxicity
Structural Patterns
Properties Categories
Analytical
data

18. Next steps
18
• Finalise report and dossiers/EALs
• Includes guidance on the read-across
methodology
• Operators and 3rd parties to be able to develop their
own EALs
• Robust and reproducible
• Consultation this autumn
• Publication of EALs
• Target – by end of March 2024

19. Contact
19
• Rick Gould
richard.gould@environment-agency.gov.uk