diff --git a/backend/lcfs/web/api/fuel_export/repo.py b/backend/lcfs/web/api/fuel_export/repo.py
index 36aeb4ce1..d09a546dc 100644
--- a/backend/lcfs/web/api/fuel_export/repo.py
+++ b/backend/lcfs/web/api/fuel_export/repo.py
@@ -260,6 +260,7 @@ async def create_fuel_export(self, fuel_export: FuelExport) -> FuelExport:
                 "fuel_type",
                 "provision_of_the_act",
                 "end_use_type",
+                "fuel_code",
             ],
         )
         return fuel_export
diff --git a/backend/lcfs/web/api/other_uses/schema.py b/backend/lcfs/web/api/other_uses/schema.py
index 51327f772..db3e591be 100644
--- a/backend/lcfs/web/api/other_uses/schema.py
+++ b/backend/lcfs/web/api/other_uses/schema.py
@@ -40,12 +40,19 @@ class ExpectedUseTypeSchema(BaseSchema):
     description: Optional[str] = None
 
 
+class FuelCategorySchema(BaseSchema):
+    fuel_category_id: int
+    category: str
+    description: Optional[str] = None
+
+
 class FuelTypeSchema(BaseSchema):
     fuel_type_id: int
     fuel_type: str
     fossil_derived: Optional[bool] = None
     provision_1_id: Optional[int] = None
     provision_2_id: Optional[int] = None
+    fuel_categories: List[FuelCategorySchema]
     default_carbon_intensity: Optional[float] = None
     fuel_codes: Optional[List[FuelCodeSchema]] = []
     provision_of_the_act: Optional[List[ProvisionOfTheActSchema]] = []
diff --git a/backend/lcfs/web/application.py b/backend/lcfs/web/application.py
index e7117a105..8aef6126c 100644
--- a/backend/lcfs/web/application.py
+++ b/backend/lcfs/web/application.py
@@ -1,4 +1,6 @@
 import logging
+import os
+import debugpy
 import uuid
 
 import structlog
diff --git a/frontend/src/assets/locales/en/allocationAgreement.json b/frontend/src/assets/locales/en/allocationAgreement.json
index 1da1af078..f120b7ebe 100644
--- a/frontend/src/assets/locales/en/allocationAgreement.json
+++ b/frontend/src/assets/locales/en/allocationAgreement.json
@@ -3,6 +3,7 @@
   "noAllocationAgreementsFound": "No allocation agreements found",
   "addAllocationAgreementRowsTitle": "Allocation agreements (e.g., allocating responsibility for fuel)",
   "allocationAgreementSubtitle": "Enter allocation agreement details below",
+  "fuelCodeFieldRequiredError": "Error updating row: Fuel code field required",
   "allocationAgreementColLabels": {
     "transaction": "Responsibility",
     "transactionPartner": "Legal name of transaction partner",
diff --git a/frontend/src/assets/locales/en/fuelExport.json b/frontend/src/assets/locales/en/fuelExport.json
index 002fba7c1..d5cf55dc6 100644
--- a/frontend/src/assets/locales/en/fuelExport.json
+++ b/frontend/src/assets/locales/en/fuelExport.json
@@ -32,5 +32,6 @@
   },
   "validateMsg": {
     "isRequired": "{{field}} is required"
-  }
+  },
+  "fuelCodeFieldRequiredError": "Error updating row: Fuel code field required"
 }
diff --git a/frontend/src/assets/locales/en/fuelSupply.json b/frontend/src/assets/locales/en/fuelSupply.json
index 3e6036080..93c75760b 100644
--- a/frontend/src/assets/locales/en/fuelSupply.json
+++ b/frontend/src/assets/locales/en/fuelSupply.json
@@ -9,6 +9,7 @@
   "LoadFailMsg": "Failed to load supply of fuel rows",
   "addRow": "Add row",
   "rows": "rows",
+  "fuelCodeFieldRequiredError": "Error updating row: Fuel code field required",
   "fuelSupplyColLabels": {
     "complianceReportId": "Compliance Report ID",
     "fuelSupplyId": "Fuel supply ID",
diff --git a/frontend/src/assets/locales/en/otherUses.json b/frontend/src/assets/locales/en/otherUses.json
index c67e328ab..70b32650d 100644
--- a/frontend/src/assets/locales/en/otherUses.json
+++ b/frontend/src/assets/locales/en/otherUses.json
@@ -21,6 +21,7 @@
   "approveConfirmText": "Are you sure you want to approve this other use entry?",
   "addRow": "Add row",
   "rows": "rows",
+  "fuelCodeFieldRequiredError": "Error updating row: Fuel code field required",
   "otherUsesColLabels": {
     "complianceReportId": "Compliance report ID",
     "fuelType": "Fuel type",
diff --git a/frontend/src/components/BCDataGrid/columns.js b/frontend/src/components/BCDataGrid/columns.js
index 0e491f34e..4e26c12cd 100644
--- a/frontend/src/components/BCDataGrid/columns.js
+++ b/frontend/src/components/BCDataGrid/columns.js
@@ -24,6 +24,7 @@ export const actions = (props) => ({
   cellRendererParams: props,
   pinned: 'left',
   maxWidth: 110,
+  minWidth: 90,
   editable: false,
   suppressKeyboardEvent,
   filter: false,
diff --git a/frontend/src/views/AllocationAgreements/AddEditAllocationAgreements.jsx b/frontend/src/views/AllocationAgreements/AddEditAllocationAgreements.jsx
index f09d3ee0e..e5a2e34c9 100644
--- a/frontend/src/views/AllocationAgreements/AddEditAllocationAgreements.jsx
+++ b/frontend/src/views/AllocationAgreements/AddEditAllocationAgreements.jsx
@@ -3,7 +3,6 @@ import BCTypography from '@/components/BCTypography'
 import Grid2 from '@mui/material/Unstable_Grid2/Grid2'
 import { useTranslation } from 'react-i18next'
 import { useLocation, useNavigate, useParams } from 'react-router-dom'
-import { BCAlert2 } from '@/components/BCAlert'
 import BCBox from '@/components/BCBox'
 import { BCGridEditor } from '@/components/BCDataGrid/BCGridEditor'
 import {
@@ -169,6 +168,29 @@ export const AddEditAllocationAgreements = () => {
         updatedData.ciOfFuel = DEFAULT_CI_FUEL[updatedData.fuelCategory]
       }
 
+      const isFuelCodeScenario =
+        params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE
+      if (isFuelCodeScenario && !updatedData.fuelCode) {
+        // Fuel code is required but not provided
+        setErrors((prevErrors) => ({
+          ...prevErrors,
+          [params.node.data.id]: ['fuelCode']
+        }))
+
+        alertRef.current?.triggerAlert({
+          message: t('allocationAgreement:fuelCodeFieldRequiredError'),
+          severity: 'error'
+        })
+
+        updatedData = {
+          ...updatedData,
+          validationStatus: 'error'
+        }
+
+        params.node.updateData(updatedData)
+        return // Stop execution, do not proceed to save
+      }
+
       try {
         setErrors({})
         await saveRow(updatedData)
diff --git a/frontend/src/views/AllocationAgreements/_schema.jsx b/frontend/src/views/AllocationAgreements/_schema.jsx
index 6e503e3dd..d90a4e212 100644
--- a/frontend/src/views/AllocationAgreements/_schema.jsx
+++ b/frontend/src/views/AllocationAgreements/_schema.jsx
@@ -196,6 +196,7 @@ export const allocationAgreementColDefs = (optionsData, errors) => [
         params.data.units = fuelType?.units
         params.data.unrecognized = fuelType?.unrecognized
         params.data.provisionOfTheAct = null
+        params.data.fuelCode = undefined
       }
       return true
     },
@@ -302,16 +303,85 @@ export const allocationAgreementColDefs = (optionsData, errors) => [
     }),
     cellStyle: (params) => {
       const style = StandardCellErrors(params, errors)
-      const conditionalStyle =
+      const isFuelCodeScenario =
         params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE
-          ? { backgroundColor: '#fff', borderColor: 'unset' }
-          : { backgroundColor: '#f2f2f2' }
+      const fuelType = optionsData?.fuelTypes?.find(
+        (obj) => params.data.fuelType === obj.fuelType
+      )
+      const fuelCodes = fuelType?.fuelCodes || []
+      const fuelCodeRequiredAndMissing =
+        isFuelCodeScenario && !params.data.fuelCode
+
+      let conditionalStyle = {}
+
+      // If required and missing, show red border and white background
+      if (fuelCodeRequiredAndMissing) {
+        style.borderColor = 'red'
+        style.backgroundColor = '#fff'
+      } else {
+        // Apply conditional styling if not missing
+        conditionalStyle =
+          isFuelCodeScenario && fuelCodes.length > 0
+            ? {
+                backgroundColor: '#fff',
+                borderColor: style.borderColor || 'unset'
+              }
+            : { backgroundColor: '#f2f2f2' }
+      }
+
       return { ...style, ...conditionalStyle }
     },
     suppressKeyboardEvent,
     minWidth: 150,
     editable: (params) =>
-      params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE,
+      params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE &&
+      optionsData?.fuelTypes?.find(
+        (obj) => params.data.fuelType === obj.fuelType
+      )?.fuelCodes?.length > 0,
+    valueGetter: (params) => {
+      const fuelTypeObj = optionsData?.fuelTypes?.find(
+        (obj) => params.data.fuelType === obj.fuelType
+      )
+      if (!fuelTypeObj) return params.data.fuelCode
+
+      const isFuelCodeScenario =
+        params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE
+      const fuelCodes =
+        fuelTypeObj.fuelCodes?.map((item) => item.fuelCode) || []
+
+      if (isFuelCodeScenario && !params.data.fuelCode) {
+        // Autopopulate if only one fuel code is available
+        if (fuelCodes.length === 1) {
+          const singleFuelCode = fuelTypeObj.fuelCodes[0]
+          params.data.fuelCode = singleFuelCode.fuelCode
+          params.data.fuelCodeId = singleFuelCode.fuelCodeId
+        }
+      }
+
+      return params.data.fuelCode
+    },
+    valueSetter: (params) => {
+      if (params.newValue) {
+        params.data.fuelCode = params.newValue
+
+        const fuelType = optionsData?.fuelTypes?.find(
+          (obj) => params.data.fuelType === obj.fuelType
+        )
+        if (params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE) {
+          const matchingFuelCode = fuelType?.fuelCodes?.find(
+            (fuelCode) => params.data.fuelCode === fuelCode.fuelCode
+          )
+          if (matchingFuelCode) {
+            params.data.fuelCodeId = matchingFuelCode.fuelCodeId
+          }
+        }
+      } else {
+        // If user clears the value
+        params.data.fuelCode = undefined
+        params.data.fuelCodeId = undefined
+      }
+      return true
+    },
     tooltipValueGetter: (p) => 'Select the approved fuel code'
   },
   {
diff --git a/frontend/src/views/FuelExports/AddEditFuelExports.jsx b/frontend/src/views/FuelExports/AddEditFuelExports.jsx
index ebaa03498..b9a40d86d 100644
--- a/frontend/src/views/FuelExports/AddEditFuelExports.jsx
+++ b/frontend/src/views/FuelExports/AddEditFuelExports.jsx
@@ -13,7 +13,11 @@ import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
 import { useTranslation } from 'react-i18next'
 import { useLocation, useNavigate, useParams } from 'react-router-dom'
 import { v4 as uuid } from 'uuid'
-import { defaultColDef, fuelExportColDefs } from './_schema'
+import {
+  defaultColDef,
+  fuelExportColDefs,
+  PROVISION_APPROVED_FUEL_CODE
+} from './_schema'
 
 export const AddEditFuelExports = () => {
   const [rowData, setRowData] = useState([])
@@ -143,7 +147,33 @@ export const AddEditFuelExports = () => {
           acc[key] = value
           return acc
         }, {})
+
       updatedData.compliancePeriod = compliancePeriod
+
+      // Local validation before saving
+      const isFuelCodeScenario =
+        params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE
+
+      if (isFuelCodeScenario && !updatedData.fuelCode) {
+        // Fuel code is required but not provided
+        setErrors((prevErrors) => ({
+          ...prevErrors,
+          [params.node.data.id]: ['fuelCode']
+        }))
+
+        alertRef.current?.triggerAlert({
+          message: t('fuelExport:fuelCodeFieldRequiredError'),
+          severity: 'error'
+        })
+
+        updatedData = {
+          ...updatedData,
+          validationStatus: 'error'
+        }
+        params.node.updateData(updatedData)
+        return // Don't proceed with save
+      }
+
       try {
         setErrors({})
         await saveRow(updatedData)
@@ -189,7 +219,7 @@ export const AddEditFuelExports = () => {
 
       params.node.updateData(updatedData)
     },
-    [saveRow, t]
+    [saveRow, t, compliancePeriod]
   )
 
   const onAction = async (action, params) => {
diff --git a/frontend/src/views/FuelExports/_schema.jsx b/frontend/src/views/FuelExports/_schema.jsx
index f113671d3..0caae593b 100644
--- a/frontend/src/views/FuelExports/_schema.jsx
+++ b/frontend/src/views/FuelExports/_schema.jsx
@@ -17,6 +17,8 @@ import {
   fuelTypeOtherConditionalStyle
 } from '@/utils/fuelTypeOther'
 
+export const PROVISION_APPROVED_FUEL_CODE = 'Fuel code - section 19 (b) (i)'
+
 const cellErrorStyle = (params, errors) => {
   let style = {}
   if (
@@ -318,29 +320,94 @@ export const fuelExportColDefs = (optionsData, errors) => [
     field: 'fuelCode',
     headerName: i18n.t('fuelExport:fuelExportColLabels.fuelCode'),
     cellEditor: 'agSelectCellEditor',
-    cellEditorParams: (params) => ({
-      values: optionsData?.fuelTypes
-        ?.find((obj) => params.data.fuelType === obj.fuelType)
-        ?.fuelCodes.map((item) => item.fuelCode)
-    }),
+    suppressKeyboardEvent,
+    minWidth: 135,
+    cellEditorParams: (params) => {
+      const fuelTypeObj = optionsData?.fuelTypes?.find(
+        (obj) => params.data.fuelType === obj.fuelType
+      )
+      return {
+        values: fuelTypeObj?.fuelCodes?.map((item) => item.fuelCode) || []
+      }
+    },
     cellStyle: (params) => {
       const style = cellErrorStyle(params, errors)
+      const fuelTypeObj = optionsData?.fuelTypes?.find(
+        (obj) => params.data.fuelType === obj.fuelType
+      )
+      const fuelCodes =
+        fuelTypeObj?.fuelCodes.map((item) => item.fuelCode) || []
+      const isFuelCodeScenario =
+        params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE
+
+      // Check if fuel code is required (scenario) but missing
+      const fuelCodeRequiredAndMissing =
+        isFuelCodeScenario && !params.data.fuelCode
+
+      if (fuelCodeRequiredAndMissing) {
+        // If required and missing, force a red border
+        style.borderColor = 'red'
+      }
+
       const conditionalStyle =
-        optionsData?.fuelTypes
-          ?.find((obj) => params.data.fuelType === obj.fuelType)
-          ?.fuelCodes.map((item) => item.fuelCode).length > 0 &&
-        /Fuel code/i.test(params.data.provisionOfTheAct)
+        fuelCodes.length > 0 &&
+        isFuelCodeScenario &&
+        !fuelCodeRequiredAndMissing
           ? { backgroundColor: '#fff', borderColor: 'unset' }
           : { backgroundColor: '#f2f2f2' }
       return { ...style, ...conditionalStyle }
     },
-    suppressKeyboardEvent,
-    minWidth: 135,
-    editable: (params) =>
-      optionsData?.fuelTypes
-        ?.find((obj) => params.data.fuelType === obj.fuelType)
-        ?.fuelCodes.map((item) => item.fuelCode).length > 0 &&
-      /Fuel code/i.test(params.data.provisionOfTheAct)
+    editable: (params) => {
+      const fuelTypeObj = optionsData?.fuelTypes?.find(
+        (obj) => params.data.fuelType === obj.fuelType
+      )
+      const fuelCodes = fuelTypeObj?.fuelCodes || []
+      return (
+        fuelCodes.length > 0 &&
+        params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE
+      )
+    },
+    valueGetter: (params) => {
+      const fuelTypeObj = optionsData?.fuelTypes?.find(
+        (obj) => params.data.fuelType === obj.fuelType
+      )
+      if (!fuelTypeObj) return params.data.fuelCode
+
+      const isFuelCodeScenario =
+        params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE
+      const fuelCodes =
+        fuelTypeObj.fuelCodes?.map((item) => item.fuelCode) || []
+
+      if (isFuelCodeScenario && !params.data.fuelCode) {
+        // Autopopulate if only one fuel code is available
+        if (fuelCodes.length === 1) {
+          const singleFuelCode = fuelTypeObj.fuelCodes[0]
+          params.data.fuelCode = singleFuelCode.fuelCode
+          params.data.fuelCodeId = singleFuelCode.fuelCodeId
+        }
+      }
+
+      return params.data.fuelCode
+    },
+    valueSetter: (params) => {
+      const newCode = params.newValue
+      const fuelTypeObj = optionsData?.fuelTypes?.find(
+        (obj) => params.data.fuelType === obj.fuelType
+      )
+      const selectedFuelCodeObj = fuelTypeObj?.fuelCodes.find(
+        (item) => item.fuelCode === newCode
+      )
+
+      if (selectedFuelCodeObj) {
+        params.data.fuelCode = selectedFuelCodeObj.fuelCode
+        params.data.fuelCodeId = selectedFuelCodeObj.fuelCodeId
+      } else {
+        params.data.fuelCode = undefined
+        params.data.fuelCodeId = undefined
+      }
+
+      return true
+    }
   },
   {
     field: 'quantity',
diff --git a/frontend/src/views/FuelSupplies/AddEditFuelSupplies.jsx b/frontend/src/views/FuelSupplies/AddEditFuelSupplies.jsx
index 7d7c4bd29..c78718694 100644
--- a/frontend/src/views/FuelSupplies/AddEditFuelSupplies.jsx
+++ b/frontend/src/views/FuelSupplies/AddEditFuelSupplies.jsx
@@ -14,7 +14,11 @@ import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
 import { useTranslation } from 'react-i18next'
 import { useLocation, useNavigate, useParams } from 'react-router-dom'
 import { v4 as uuid } from 'uuid'
-import { defaultColDef, fuelSupplyColDefs } from './_schema'
+import {
+  defaultColDef,
+  fuelSupplyColDefs,
+  PROVISION_APPROVED_FUEL_CODE
+} from './_schema'
 
 export const AddEditFuelSupplies = () => {
   const [rowData, setRowData] = useState([])
@@ -131,15 +135,6 @@ export const AddEditFuelSupplies = () => {
             'fuelCategory',
             fuelCategoryOptions[0] ?? null
           )
-
-          const fuelCodeOptions = selectedFuelType.fuelCodes.map(
-            (code) => code.fuelCode
-          )
-          params.node.setDataValue('fuelCode', fuelCodeOptions[0] ?? null)
-          params.node.setDataValue(
-            'fuelCodeId',
-            selectedFuelType.fuelCodes[0]?.fuelCodeId ?? null
-          )
         }
       }
     },
@@ -164,6 +159,28 @@ export const AddEditFuelSupplies = () => {
       if (updatedData.fuelType === 'Other') {
         updatedData.ciOfFuel = DEFAULT_CI_FUEL[updatedData.fuelCategory]
       }
+
+      const isFuelCodeScenario =
+        params.node.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE
+      if (isFuelCodeScenario && !params.node.data.fuelCode) {
+        // Set error on the row
+        setErrors({
+          [params.node.data.id]: ['fuelCode']
+        })
+
+        alertRef.current?.triggerAlert({
+          message: t('fuelSupply:fuelCodeFieldRequiredError'),
+          severity: 'error'
+        })
+
+        // Update node data to reflect error state
+        params.node.updateData({
+          ...params.node.data,
+          validationStatus: 'error'
+        })
+        return // Stop saving further
+      }
+
       try {
         setErrors({})
         await saveRow(updatedData)
diff --git a/frontend/src/views/FuelSupplies/_schema.jsx b/frontend/src/views/FuelSupplies/_schema.jsx
index 912dc994d..0dc792d73 100644
--- a/frontend/src/views/FuelSupplies/_schema.jsx
+++ b/frontend/src/views/FuelSupplies/_schema.jsx
@@ -19,6 +19,8 @@ import {
 } from '@/utils/grid/errorRenderers'
 import { apiRoutes } from '@/constants/routes'
 
+export const PROVISION_APPROVED_FUEL_CODE = 'Fuel code - section 19 (b) (i)'
+
 export const fuelSupplyColDefs = (optionsData, errors, warnings) => [
   validation,
   actions({
@@ -292,21 +294,35 @@ export const fuelSupplyColDefs = (optionsData, errors, warnings) => [
     field: 'fuelCode',
     headerName: i18n.t('fuelSupply:fuelSupplyColLabels.fuelCode'),
     cellEditor: 'agSelectCellEditor',
-    cellEditorParams: (params) => ({
-      values: optionsData?.fuelTypes
-        ?.find((obj) => params.data.fuelType === obj.fuelType)
-        ?.fuelCodes.map((item) => item.fuelCode)
-    }),
+    cellEditorParams: (params) => {
+      const fuelType = optionsData?.fuelTypes?.find(
+        (obj) => params.data.fuelType === obj.fuelType
+      )
+      return {
+        values: fuelType?.fuelCodes.map((item) => item.fuelCode) || []
+      }
+    },
     cellStyle: (params) => {
       const style = StandardCellWarningAndErrors(params, errors, warnings)
-      const conditionalStyle =
-        optionsData?.fuelTypes
-          ?.find((obj) => params.data.fuelType === obj.fuelType)
-          ?.fuelCodes.map((item) => item.fuelCode).length > 0 &&
-        /Fuel code/i.test(params.data.provisionOfTheAct)
-          ? { backgroundColor: '#fff' }
-          : { backgroundColor: '#f2f2f2', borderColor: 'unset' }
-      return { ...style, ...conditionalStyle }
+      const isFuelCodeScenario =
+        params.data?.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE
+      const fuelType = optionsData?.fuelTypes?.find(
+        (obj) => params.data.fuelType === obj.fuelType
+      )
+      const fuelCodes = fuelType?.fuelCodes || []
+      const fuelCodeRequiredAndMissing =
+        isFuelCodeScenario && !params.data.fuelCode
+
+      if (fuelCodeRequiredAndMissing) {
+        // Highlight the cell if fuel code is required but not selected
+        return { ...style, backgroundColor: '#fff', borderColor: 'red' }
+      } else if (isFuelCodeScenario && fuelCodes.length > 0) {
+        // Allow selection when scenario matches and codes are present
+        return { ...style, backgroundColor: '#fff', borderColor: 'unset' }
+      } else {
+        // Otherwise disabled styling
+        return { ...style, backgroundColor: '#f2f2f2', borderColor: 'unset' }
+      }
     },
     suppressKeyboardEvent,
     minWidth: 135,
@@ -314,29 +330,50 @@ export const fuelSupplyColDefs = (optionsData, errors, warnings) => [
       const fuelType = optionsData?.fuelTypes?.find(
         (obj) => params.data.fuelType === obj.fuelType
       )
-      if (fuelType) {
-        return (
-          fuelType.fuelCodes.map((item) => item.fuelCode).length > 0 &&
-          /Fuel code/i.test(params.data.provisionOfTheAct)
-        )
+      return (
+        params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE &&
+        fuelType?.fuelCodes?.length > 0
+      )
+    },
+    valueGetter: (params) => {
+      const fuelType = optionsData?.fuelTypes?.find(
+        (obj) => params.data.fuelType === obj.fuelType
+      )
+      if (!fuelType) return params.data.fuelCode
+
+      const isFuelCodeScenario =
+        params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE
+      const fuelCodes = fuelType?.fuelCodes?.map((item) => item.fuelCode) || []
+
+      if (isFuelCodeScenario && !params.data.fuelCode) {
+        // If only one code is available, auto-populate
+        if (fuelCodes.length === 1) {
+          const singleFuelCode = fuelType.fuelCodes[0]
+          params.data.fuelCode = singleFuelCode.fuelCode
+          params.data.fuelCodeId = singleFuelCode.fuelCodeId
+        }
       }
-      return false
+
+      return params.data.fuelCode
     },
     valueSetter: (params) => {
       if (params.newValue) {
         params.data.fuelCode = params.newValue
-
         const fuelType = optionsData?.fuelTypes?.find(
           (obj) => params.data.fuelType === obj.fuelType
         )
-        if (/Fuel code/i.test(params.data.provisionOfTheAct)) {
-          const matchingFuelCode = fuelType.fuelCodes?.find(
+        if (params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE) {
+          const matchingFuelCode = fuelType?.fuelCodes?.find(
             (fuelCode) => params.data.fuelCode === fuelCode.fuelCode
           )
           if (matchingFuelCode) {
             params.data.fuelCodeId = matchingFuelCode.fuelCodeId
           }
         }
+      } else {
+        // If user clears the value
+        params.data.fuelCode = undefined
+        params.data.fuelCodeId = undefined
       }
       return true
     }
diff --git a/frontend/src/views/OtherUses/AddEditOtherUses.jsx b/frontend/src/views/OtherUses/AddEditOtherUses.jsx
index bbd553ca3..885675c30 100644
--- a/frontend/src/views/OtherUses/AddEditOtherUses.jsx
+++ b/frontend/src/views/OtherUses/AddEditOtherUses.jsx
@@ -1,5 +1,4 @@
-import { BCAlert2 } from '@/components/BCAlert'
-import BCButton from '@/components/BCButton'
+
 import { BCGridEditor } from '@/components/BCDataGrid/BCGridEditor'
 import Loading from '@/components/Loading'
 import {
@@ -8,16 +7,17 @@ import {
   useSaveOtherUses
 } from '@/hooks/useOtherUses'
 import { cleanEmptyStringValues } from '@/utils/formatters'
-import { faFloppyDisk } from '@fortawesome/free-solid-svg-icons'
-import { FontAwesomeIcon } from '@fortawesome/react-fontawesome'
-import { Stack } from '@mui/material'
 import BCTypography from '@/components/BCTypography'
 import Grid2 from '@mui/material/Unstable_Grid2/Grid2'
-import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
+import { useCallback, useEffect, useRef, useState } from 'react'
 import { useTranslation } from 'react-i18next'
 import { useLocation, useNavigate, useParams } from 'react-router-dom'
 import { v4 as uuid } from 'uuid'
-import { defaultColDef, otherUsesColDefs, PROVISION_APPROVED_FUEL_CODE} from './_schema'
+import {
+  defaultColDef,
+  otherUsesColDefs,
+  PROVISION_APPROVED_FUEL_CODE
+} from './_schema'
 import * as ROUTES from '@/constants/routes/routes.js'
 
 export const AddEditOtherUses = () => {
@@ -55,31 +55,31 @@ export const AddEditOtherUses = () => {
         rows.map((row) => ({
           ...row,
           id: row.id || uuid(),
-          isValid: true,
-        }));
+          isValid: true
+        }))
 
-      setRowData(ensureRowIds(otherUses));
+      setRowData(ensureRowIds(otherUses))
     }
-  }, [otherUses]);
+  }, [otherUses])
 
   const findCiOfFuel = useCallback((data, optionsData) => {
-    let ciOfFuel = 0;
+    let ciOfFuel = 0
     if (data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE) {
       const fuelType = optionsData?.fuelTypes?.find(
         (obj) => data.fuelType === obj.fuelType
-      );
+      )
       const fuelCode = fuelType?.fuelCodes?.find(
         (item) => item.fuelCode === data.fuelCode
-      );
-      ciOfFuel = fuelCode?.carbonIntensity || 0;
+      )
+      ciOfFuel = fuelCode?.carbonIntensity || 0
     } else {
       const fuelType = optionsData?.fuelTypes?.find(
         (obj) => data.fuelType === obj.fuelType
-      );
-      ciOfFuel = fuelType?.defaultCarbonIntensity || 0;
+      )
+      ciOfFuel = fuelType?.defaultCarbonIntensity || 0
     }
-    return ciOfFuel;
-  }, []);
+    return ciOfFuel
+  }, [])
 
   const onGridReady = (params) => {
     const ensureRowIds = (rows) => {
@@ -151,20 +151,39 @@ export const AddEditOtherUses = () => {
         const ciOfFuel = findCiOfFuel(params.data, optionsData)
         params.node.setDataValue('ciOfFuel', ciOfFuel)
 
-        // Auto-populate the "Unit" field based on the selected fuel type
-      if (params.colDef.field === 'fuelType') {
-        const fuelType = optionsData?.fuelTypes?.find(
-          (obj) => params.data.fuelType === obj.fuelType
-        );
-        if (fuelType && fuelType.units) {
-          params.node.setDataValue('units', fuelType.units);
-        } else {
-          params.node.setDataValue('units', '');
+        // Auto-populate fields based on the selected fuel type
+        if (params.colDef.field === 'fuelType') {
+          const fuelType = optionsData?.fuelTypes?.find(
+            (obj) => params.data.fuelType === obj.fuelType
+          );
+          if (fuelType) {
+            // Auto-populate the "units" field
+            if (fuelType.units) {
+              params.node.setDataValue('units', fuelType.units);
+            } else {
+              params.node.setDataValue('units', '');
+            }
+
+            // Auto-populate the "fuelCategory" field
+            const fuelCategoryOptions = fuelType.fuelCategories.map(
+              (item) => item.category
+            );
+            params.node.setDataValue('fuelCategory', fuelCategoryOptions[0] ?? null);
+
+            // Auto-populate the "fuelCode" field
+            const fuelCodeOptions = fuelType.fuelCodes.map(
+              (code) => code.fuelCode
+            );
+            params.node.setDataValue('fuelCode', fuelCodeOptions[0] ?? null);
+            params.node.setDataValue(
+              'fuelCodeId',
+              fuelType.fuelCodes[0]?.fuelCodeId ?? null
+            );
+          }
         }
       }
-      }
     },
-    [optionsData]
+    [optionsData, findCiOfFuel]
   )
 
   const onCellEditingStopped = useCallback(
@@ -181,6 +200,29 @@ export const AddEditOtherUses = () => {
       // clean up any null or empty string values
       let updatedData = cleanEmptyStringValues(params.data)
 
+      const isFuelCodeScenario =
+        params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE
+      if (isFuelCodeScenario && !updatedData.fuelCode) {
+        // Fuel code is required but not provided
+        setErrors((prevErrors) => ({
+          ...prevErrors,
+          [params.node.data.id]: ['fuelCode']
+        }))
+
+        alertRef.current?.triggerAlert({
+          message: t('otherUses:fuelCodeFieldRequiredError'),
+          severity: 'error'
+        })
+
+        updatedData = {
+          ...updatedData,
+          validationStatus: 'error'
+        }
+
+        params.node.updateData(updatedData)
+        return // Stop execution, do not proceed to save
+      }
+
       try {
         setErrors({})
         await saveRow(updatedData)
diff --git a/frontend/src/views/OtherUses/_schema.jsx b/frontend/src/views/OtherUses/_schema.jsx
index 9af82de0b..03ce751fb 100644
--- a/frontend/src/views/OtherUses/_schema.jsx
+++ b/frontend/src/views/OtherUses/_schema.jsx
@@ -23,7 +23,7 @@ export const otherUsesColDefs = (optionsData, errors) => [
     hide: true
   },
   {
-    field:'otherUsesId',
+    field: 'otherUsesId',
     hide: true
   },
   {
@@ -42,19 +42,32 @@ export const otherUsesColDefs = (optionsData, errors) => [
     suppressKeyboardEvent,
     cellRenderer: (params) =>
       params.value || <BCTypography variant="body4">Select</BCTypography>,
-    cellStyle: (params) => StandardCellErrors(params, errors)
+    cellStyle: (params) => StandardCellErrors(params, errors),
+    valueSetter: (params) => {
+      if (params.newValue) {
+        // TODO: Evaluate if additional fields need to be reset when fuel type changes
+        params.data.fuelType = params.newValue
+        params.data.fuelCode = undefined
+      }
+      return true
+    }
   },
   {
     field: 'fuelCategory',
     headerName: i18n.t('otherUses:otherUsesColLabels.fuelCategory'),
     headerComponent: RequiredHeader,
     cellEditor: AutocompleteCellEditor,
-    cellEditorParams: {
-      options: optionsData.fuelCategories.map((obj) => obj.category),
-      multiple: false,
-      disableCloseOnSelect: false,
-      freeSolo: false,
-      openOnFocus: true
+    cellEditorParams: (params) => {
+      const fuelType = optionsData?.fuelTypes?.find(
+        (obj) => params.data.fuelType === obj.fuelType
+      );
+      return {
+        options: fuelType ? fuelType.fuelCategories.map((item) => item.category) : [],
+        multiple: false,
+        disableCloseOnSelect: false,
+        freeSolo: false,
+        openOnFocus: true
+      };
     },
     suppressKeyboardEvent,
     cellRenderer: (params) =>
@@ -65,9 +78,7 @@ export const otherUsesColDefs = (optionsData, errors) => [
   {
     field: 'provisionOfTheAct',
     headerComponent: RequiredHeader,
-    headerName: i18n.t(
-      'otherUses:otherUsesColLabels.provisionOfTheAct'
-    ),
+    headerName: i18n.t('otherUses:otherUsesColLabels.provisionOfTheAct'),
     cellEditor: 'agSelectCellEditor',
     cellEditorParams: (params) => {
       const fuelType = optionsData?.fuelTypes?.find(
@@ -89,11 +100,11 @@ export const otherUsesColDefs = (optionsData, errors) => [
     suppressKeyboardEvent,
     valueSetter: (params) => {
       if (params.newValue !== params.oldValue) {
-        params.data.provisionOfTheAct = params.newValue;
-        params.data.fuelCode = ''; // Reset fuelCode when provisionOfTheAct changes
-        return true;
+        params.data.provisionOfTheAct = params.newValue
+        params.data.fuelCode = '' // Reset fuelCode when provisionOfTheAct changes
+        return true
       }
-      return false;
+      return false
     },
     minWidth: 300,
     editable: true,
@@ -105,61 +116,91 @@ export const otherUsesColDefs = (optionsData, errors) => [
     headerName: i18n.t('otherUses:otherUsesColLabels.fuelCode'),
     cellEditor: AutocompleteCellEditor,
     cellEditorParams: (params) => {
-        const fuelType = optionsData?.fuelTypes?.find((obj) => params.data.fuelType === obj.fuelType);
+      const fuelType = optionsData?.fuelTypes?.find(
+        (obj) => params.data.fuelType === obj.fuelType
+      )
 
-        return {
-            options: fuelType?.fuelCodes?.map((item) => item.fuelCode) || [], // Safely access fuelCodes
-            multiple: false,
-            disableCloseOnSelect: false,
-            freeSolo: false,
-            openOnFocus: true
-        };
+      return {
+        options: fuelType?.fuelCodes?.map((item) => item.fuelCode) || [], // Safely access fuelCodes
+        multiple: false,
+        disableCloseOnSelect: false,
+        freeSolo: false,
+        openOnFocus: true
+      }
     },
     cellRenderer: (params) => {
-      const fuelType = optionsData?.fuelTypes?.find((obj) => params.data.fuelType === obj.fuelType);
+      const fuelType = optionsData?.fuelTypes?.find(
+        (obj) => params.data.fuelType === obj.fuelType
+      )
       if (
         params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE &&
         fuelType?.fuelCodes?.length > 0
       ) {
-        return params.value || <BCTypography variant="body4">Select</BCTypography>;
+        return (
+          params.value || <BCTypography variant="body4">Select</BCTypography>
+        )
       }
-      return null;
+      return null
     },
     cellStyle: (params) => {
-        const style = StandardCellErrors(params, errors);
-        const conditionalStyle =
-            params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE &&
-            optionsData?.fuelTypes
-                ?.find((obj) => params.data.fuelType === obj.fuelType)
-                ?.fuelCodes?.length > 0
-                ? { backgroundColor: '#fff', borderColor: 'unset' }
-                : { backgroundColor: '#f2f2f2' };
-        return { ...style, ...conditionalStyle };
+      const style = StandardCellErrors(params, errors)
+      const isFuelCodeScenario =
+        params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE
+      const fuelType = optionsData?.fuelTypes?.find(
+        (obj) => params.data.fuelType === obj.fuelType
+      )
+      const fuelCodes = fuelType?.fuelCodes || []
+      const fuelCodeRequiredAndMissing =
+        isFuelCodeScenario && !params.data.fuelCode
+
+      // If required and missing, show red border
+      if (fuelCodeRequiredAndMissing) {
+        style.borderColor = 'red'
+      }
+
+      const conditionalStyle =
+        isFuelCodeScenario &&
+        fuelCodes.length > 0 &&
+        !fuelCodeRequiredAndMissing
+          ? {
+              backgroundColor: '#fff',
+              borderColor: style.borderColor || 'unset'
+            }
+          : { backgroundColor: '#f2f2f2' }
+
+      return { ...style, ...conditionalStyle }
     },
     suppressKeyboardEvent,
     minWidth: 150,
     editable: (params) => {
-      const fuelType = optionsData?.fuelTypes?.find((obj) => params.data.fuelType === obj.fuelType);
+      const fuelType = optionsData?.fuelTypes?.find(
+        (obj) => params.data.fuelType === obj.fuelType
+      )
       return (
         params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE &&
         fuelType?.fuelCodes?.length > 0
-      );
+      )
     },
-    valueSetter: (params) => {
-        if (params.newValue) {
-            params.data.fuelCode = params.newValue;
+    valueGetter: (params) => {
+      const isFuelCodeScenario =
+        params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE
+      const fuelType = optionsData?.fuelTypes?.find(
+        (obj) => params.data.fuelType === obj.fuelType
+      )
+      const fuelCodes = fuelType?.fuelCodes || []
 
-            const fuelType = optionsData?.fuelTypes?.find((obj) => params.data.fuelType === obj.fuelType);
-            if (params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE) {
-                const matchingFuelCode = fuelType?.fuelCodes?.find(
-                    (fuelCode) => params.data.fuelCode === fuelCode.fuelCode
-                );
-                if (matchingFuelCode) {
-                    params.data.fuelCodeId = matchingFuelCode.fuelCodeId;
-                }
-            }
-        }
-        return true;
+      if (
+        isFuelCodeScenario &&
+        !params.data.fuelCode &&
+        fuelCodes.length === 1
+      ) {
+        // Autopopulate if only one fuel code is available
+        const singleFuelCode = fuelCodes[0]
+        params.data.fuelCode = singleFuelCode.fuelCode
+        params.data.fuelCodeId = singleFuelCode.fuelCodeId
+      }
+
+      return params.data.fuelCode
     },
     tooltipValueGetter: (p) => 'Select the approved fuel code'
   },
@@ -207,31 +248,31 @@ export const otherUsesColDefs = (optionsData, errors) => [
     valueGetter: (params) => {
       const fuelType = optionsData?.fuelTypes?.find(
         (obj) => params.data.fuelType === obj.fuelType
-      );
+      )
 
       if (params.data.provisionOfTheAct === PROVISION_APPROVED_FUEL_CODE) {
         return (
           fuelType?.fuelCodes?.find(
             (item) => item.fuelCode === params.data.fuelCode
           )?.carbonIntensity || 0
-        );
+        )
       }
       if (fuelType) {
         if (params.data.fuelType === 'Other' && params.data.fuelCategory) {
-          const categories = fuelType.fuelCategories;
+          const categories = fuelType.fuelCategories
           const defaultCI = categories?.find(
             (cat) => cat.category === params.data.fuelCategory
-          )?.defaultAndPrescribedCi;
+          )?.defaultAndPrescribedCi
 
-          return defaultCI || 0;
+          return defaultCI || 0
         }
 
-        return fuelType.defaultCarbonIntensity || 0;
+        return fuelType.defaultCarbonIntensity || 0
       }
 
-      return 0;
+      return 0
     },
-    minWidth: 150,
+    minWidth: 150
   },
   {
     field: 'expectedUse',