diff --git a/.gitignore b/.gitignore
index b7bfa02..8f8d464 100644
--- a/.gitignore
+++ b/.gitignore
@@ -90,4 +90,5 @@ sw.*
 # Vim swap files
 *.swp
 
-test
\ No newline at end of file
+test
+TODO
\ No newline at end of file
diff --git a/package.json b/package.json
index fafec3c..c175870 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@tornado/tornado-oracles",
-  "version": "1.0.0",
+  "version": "1.1.0",
   "description": "Gas oracle for Tornado-specific transactions",
   "main": "./lib/index.js",
   "types": "./lib/index.d.ts",
diff --git a/src/feeOracle.ts b/src/feeOracle.ts
index 8dde27b..33ee0b7 100644
--- a/src/feeOracle.ts
+++ b/src/feeOracle.ts
@@ -23,14 +23,15 @@ export abstract class TornadoFeeOracle implements ITornadoFeeOracle {
    * Because Optimism transaction published on Mainnet, for each OP transaction we need to calculate L1 security fee:
    * https://community.optimism.io/docs/developers/build/transaction-fees/#priority-fee
    * @param {TransactionData} tx Transaction data to estimate L1 additional fee
-   * @returns Fee in WEI (MATIC)
+   * @returns {Promise<string>} Fee in WEI (MATIC)
    */
-  private async fetchL1OptimismFee(tx?: TransactionData): Promise<BigNumber> {
-    if (this.chainId != ChainId.OPTIMISM) return BigNumber.from(0);
+  async fetchL1OptimismFee(tx?: TransactionData): Promise<string> {
+    if (this.chainId != ChainId.OPTIMISM) return BigNumber.from(0).toHexString();
 
     const optimismL1FeeOracle = getOptimismL1FeeOracle(this.provider);
+    const l1Fee = await optimismL1FeeOracle.getL1Fee(serializeTx(tx));
 
-    return await optimismL1FeeOracle.getL1Fee(serializeTx(tx));
+    return l1Fee.toHexString();
   }
 
   /**
@@ -40,11 +41,7 @@ export abstract class TornadoFeeOracle implements ITornadoFeeOracle {
    * @param {LegacyGasPriceKey} speed Preferred transaction speed, if uses legacy gas (before EIP-1559)
    * @returns {Promise<string>} Gas value in WEI (hex-format)
    */
-  public async getGas(
-    tx?: TransactionData,
-    txType: TxType = 'other',
-    speed: LegacyGasPriceKey = 'fast',
-  ): Promise<string> {
+  async getGas(tx?: TransactionData, txType: TxType = 'other', speed: LegacyGasPriceKey = 'fast'): Promise<string> {
     const gasPrice = await this.getGasPrice(txType, speed);
     let gas = BigNumber.from(0);
     gas = gas.add(gasPrice);
diff --git a/src/types.ts b/src/types.ts
index 1935f02..b6531e4 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -35,6 +35,7 @@ export interface ITornadoFeeOracle {
   getGasPriceParams: (type?: TxType, speed?: LegacyGasPriceKey, bumpPercent?: number) => Promise<GasPriceParams>;
   getGasPrice: (type?: TxType, speed?: LegacyGasPriceKey, bumpPercent?: number) => Promise<string>;
   getGasLimit: (tx?: TransactionData, type?: TxType, bumpPercent?: number) => Promise<number>;
+  fetchL1OptimismFee: (tx?: TransactionData) => Promise<string>;
   calculateRefundInETH: (tx?: TransactionData) => Promise<string>;
   calculateRefundInToken: (
     tokenPriceInEth: BigNumberish,