diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 013f1a81aa6..598a058edbb 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -16,10 +16,11 @@ Test fixtures for use by clients are available for each release on the [Github r
 - 🔀 Refactor `ethereum_test_fixtures` and `ethereum_clis` to create `FixtureConsumer` and `FixtureConsumerTool` classes which abstract away the consumption process used by `consume direct` ([#935](https://github.com/ethereum/execution-spec-tests/pull/935)).
 - ✨ Allow `consume direct --collect-only` without specifying a fixture consumer binary on the command-line ([#1237](https://github.com/ethereum/execution-spec-tests/pull/1237)).
 - ✨ Allow `fill --collect-only` without the need for existence of the folder `./fixtures'
-- ✨ Report the (resolved) fixture tarball URL and local fixture cache directory when `consume`'s `--input` flag is a release spec or URL  [#1239](https://github.com/ethereum/execution-spec-tests/pull/1239).
+- ✨ Report the (resolved) fixture tarball URL and local fixture cache directory when `consume`'s `--input` flag is a release spec or URL ([#1239](https://github.com/ethereum/execution-spec-tests/pull/1239)).
 - ✨ EOF Container validation tests (`eof_test`) now generate container deployment state tests, by wrapping the EOF container in an init-container and sending a deploy transaction ([#783](https://github.com/ethereum/execution-spec-tests/pull/783), [#1233](https://github.com/ethereum/execution-spec-tests/pull/1233)).
 - ✨ Use regexes for Hive's `--sim.limit` argument and don't use xdist if `--sim.parallelism==1` in the `eest/consume-rlp` and `eest/consume-rlp` simulators ([#1220](https://github.com/ethereum/execution-spec-tests/pull/1220)).
 - 🐞 Register generated test markers, e.g., `blockchain_test_from_state_test`, to prevent test session warnings ([#1238](https://github.com/ethereum/execution-spec-tests/pull/1238), [#1245](https://github.com/ethereum/execution-spec-tests/pull/1245)).
+- 🐞 Zero-pad `Environment` fields passed to `t8n` tools as required by `evmone-t8n` ([#1268](https://github.com/ethereum/execution-spec-tests/pull/1268)).
 
 ### 📋 Misc
 
diff --git a/src/ethereum_test_types/tests/test_types.py b/src/ethereum_test_types/tests/test_types.py
index 444e67c269a..883b52ea929 100644
--- a/src/ethereum_test_types/tests/test_types.py
+++ b/src/ethereum_test_types/tests/test_types.py
@@ -442,9 +442,9 @@ def test_account_merge(
             Environment(),
             {
                 "currentCoinbase": "0x2adc25665018aa1fe0e6bc666dac8fc2697ff9ba",
-                "currentGasLimit": "0x16345785d8a0000",
-                "currentNumber": "0x1",
-                "currentTimestamp": "0x3e8",
+                "currentGasLimit": "0x016345785d8a0000",
+                "currentNumber": "0x01",
+                "currentTimestamp": "0x03e8",
                 "blockHashes": {},
                 "ommers": [],
                 "parentUncleHash": (
@@ -475,17 +475,17 @@ def test_account_merge(
             ),
             {
                 "currentCoinbase": "0x0000000000000000000000000000000000001234",
-                "currentGasLimit": "0x16345785d8a0000",
-                "currentNumber": "0x1",
-                "currentTimestamp": "0x3e8",
-                "currentDifficulty": "0x5",
-                "currentRandom": "0x6",
-                "currentBaseFee": "0x7",
-                "parentDifficulty": "0x8",
-                "parentTimestamp": "0x9",
-                "parentBaseFee": "0xa",
-                "parentGasUsed": "0xb",
-                "parentGasLimit": "0xc",
+                "currentGasLimit": "0x016345785d8a0000",
+                "currentNumber": "0x01",
+                "currentTimestamp": "0x03e8",
+                "currentDifficulty": "0x05",
+                "currentRandom": "0x06",
+                "currentBaseFee": "0x07",
+                "parentDifficulty": "0x08",
+                "parentTimestamp": "0x09",
+                "parentBaseFee": "0x0a",
+                "parentGasUsed": "0x0b",
+                "parentGasLimit": "0x0c",
                 "parentUncleHash": (
                     "0x000000000000000000000000000000000000000000000000000000000000000d"
                 ),
@@ -497,8 +497,8 @@ def test_account_merge(
                         "amount": "0x2",
                     },
                 ],
-                "parentBlobGasUsed": "0xe",
-                "parentExcessBlobGas": "0xf",
+                "parentBlobGasUsed": "0x0e",
+                "parentExcessBlobGas": "0x0f",
                 "currentBlobGasUsed": "0x10",
                 "currentExcessBlobGas": "0x11",
                 "blockHashes": {
diff --git a/src/ethereum_test_types/types.py b/src/ethereum_test_types/types.py
index deb59561bc9..2643306d714 100644
--- a/src/ethereum_test_types/types.py
+++ b/src/ethereum_test_types/types.py
@@ -42,6 +42,7 @@
     StorageRootType,
     TestAddress,
     TestPrivateKey,
+    ZeroPaddedHexNumber,
 )
 from ethereum_test_base_types import Alloc as BaseAlloc
 from ethereum_test_base_types.conversions import (
@@ -352,16 +353,16 @@ class EnvironmentGeneric(CamelModel, Generic[NumberBoundTypeVar]):
     parent_gas_limit: NumberBoundTypeVar | None = Field(None)
 
 
-class Environment(EnvironmentGeneric[HexNumber]):
+class Environment(EnvironmentGeneric[ZeroPaddedHexNumber]):
     """
     Structure used to keep track of the context in which a block
     must be executed.
     """
 
-    blob_gas_used: HexNumber | None = Field(None, alias="currentBlobGasUsed")
+    blob_gas_used: ZeroPaddedHexNumber | None = Field(None, alias="currentBlobGasUsed")
     parent_ommers_hash: Hash = Field(Hash(EmptyOmmersRoot), alias="parentUncleHash")
-    parent_blob_gas_used: HexNumber | None = Field(None)
-    parent_excess_blob_gas: HexNumber | None = Field(None)
+    parent_blob_gas_used: ZeroPaddedHexNumber | None = Field(None)
+    parent_excess_blob_gas: ZeroPaddedHexNumber | None = Field(None)
     parent_beacon_block_root: Hash | None = Field(None)
 
     block_hashes: Dict[Number, Hash] = Field(default_factory=dict)