diff --git a/packages/horizon/hardhat.config.ts b/packages/horizon/hardhat.config.ts
index 57f1d8f89..6a57472a5 100644
--- a/packages/horizon/hardhat.config.ts
+++ b/packages/horizon/hardhat.config.ts
@@ -3,6 +3,7 @@ import '@nomicfoundation/hardhat-toolbox'
 import '@nomicfoundation/hardhat-ignition-ethers'
 import 'hardhat-storage-layout'
 import 'hardhat-contract-sizer'
+import 'hardhat-secure-accounts'
 
 import { HardhatUserConfig } from 'hardhat/config'
 
@@ -20,17 +21,20 @@ const config: HardhatUserConfig = {
     artifacts: './build/contracts',
     sources: './contracts',
   },
+  secureAccounts: {
+    enabled: true,
+  },
   networks: {
     hardhat: {
+      secureAccounts: {
+        enabled: false,
+      },
       accounts: {
         mnemonic: 'myth like bonus scare over problem client lizard pioneer submit female collect',
       },
     },
     arbitrumSepolia: {
       url: 'https://sepolia-rollup.arbitrum.io/rpc',
-      accounts: {
-        mnemonic: process.env.MNEMONIC ?? '',
-      },
     },
   },
   etherscan: {
diff --git a/packages/horizon/package.json b/packages/horizon/package.json
index 4c6624051..7c3d26153 100644
--- a/packages/horizon/package.json
+++ b/packages/horizon/package.json
@@ -37,6 +37,7 @@
     "hardhat": "^2.20.1",
     "hardhat-contract-sizer": "^2.10.0",
     "hardhat-gas-reporter": "^1.0.8",
+    "hardhat-secure-accounts": "^1.0.4",
     "hardhat-storage-layout": "^0.1.7",
     "lint-staged": "^15.2.2",
     "prettier": "^3.2.5",
diff --git a/packages/subgraph-service/hardhat.config.ts b/packages/subgraph-service/hardhat.config.ts
index b173873fb..a1158bb8b 100644
--- a/packages/subgraph-service/hardhat.config.ts
+++ b/packages/subgraph-service/hardhat.config.ts
@@ -3,6 +3,7 @@ import '@nomicfoundation/hardhat-ignition-ethers'
 import '@nomicfoundation/hardhat-toolbox'
 import 'hardhat-contract-sizer'
 import 'hardhat-storage-layout'
+import 'hardhat-secure-accounts'
 import 'solidity-docgen'
 
 import { HardhatUserConfig } from 'hardhat/config'
@@ -21,6 +22,22 @@ const config: HardhatUserConfig = {
     artifacts: './build/contracts',
     sources: './contracts',
   },
+  secureAccounts: {
+    enabled: true,
+  },
+  networks: {
+    hardhat: {
+      secureAccounts: {
+        enabled: false,
+      },
+      accounts: {
+        mnemonic: 'myth like bonus scare over problem client lizard pioneer submit female collect',
+      },
+    },
+    arbitrumSepolia: {
+      url: 'https://sepolia-rollup.arbitrum.io/rpc',
+    },
+  },
 }
 
 export default config
diff --git a/packages/subgraph-service/package.json b/packages/subgraph-service/package.json
index 419d5f160..f9094be53 100644
--- a/packages/subgraph-service/package.json
+++ b/packages/subgraph-service/package.json
@@ -38,6 +38,7 @@
     "hardhat": "^2.20.1",
     "hardhat-contract-sizer": "^2.10.0",
     "hardhat-gas-reporter": "^1.0.8",
+    "hardhat-secure-accounts": "^1.0.4",
     "hardhat-storage-layout": "^0.1.7",
     "lint-staged": "^15.2.2",
     "prettier": "^3.2.5",
diff --git a/yarn.lock b/yarn.lock
index 4cfd396f1..c6850b143 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2953,6 +2953,7 @@ __metadata:
     hardhat: "npm:^2.20.1"
     hardhat-contract-sizer: "npm:^2.10.0"
     hardhat-gas-reporter: "npm:^1.0.8"
+    hardhat-secure-accounts: "npm:^1.0.4"
     hardhat-storage-layout: "npm:^0.1.7"
     lint-staged: "npm:^15.2.2"
     prettier: "npm:^3.2.5"
@@ -3046,6 +3047,7 @@ __metadata:
     hardhat: "npm:^2.20.1"
     hardhat-contract-sizer: "npm:^2.10.0"
     hardhat-gas-reporter: "npm:^1.0.8"
+    hardhat-secure-accounts: "npm:^1.0.4"
     hardhat-storage-layout: "npm:^0.1.7"
     lint-staged: "npm:^15.2.2"
     prettier: "npm:^3.2.5"
@@ -14246,6 +14248,22 @@ __metadata:
   languageName: node
   linkType: hard
 
+"hardhat-secure-accounts@npm:^1.0.4":
+  version: 1.0.4
+  resolution: "hardhat-secure-accounts@npm:1.0.4"
+  dependencies:
+    debug: "npm:^4.3.4"
+    enquirer: "npm:^2.3.6"
+    lodash.clonedeep: "npm:^4.5.0"
+    prompt-sync: "npm:^4.2.0"
+  peerDependencies:
+    "@nomicfoundation/hardhat-ethers": ^3.0.0
+    ethers: ^6.13.0
+    hardhat: ^2.22.0
+  checksum: 6406be693502234f342b9e27215bb3ecb3502a0d9f5299c5c1f5e1be28f08d26226cff511723e719639dc12fb2e4e329386a41e5c90f57b3bf3116656c45c2b5
+  languageName: node
+  linkType: hard
+
 "hardhat-storage-layout@npm:0.1.6":
   version: 0.1.6
   resolution: "hardhat-storage-layout@npm:0.1.6"