Conversion failed when converting the varchar value '2,4,6' to data type int on Multi-Select Stored Procedure

I am getting an error when passing in a multi-select string consisting of multiple parameters.  

The multi-select values are being passed in through @LOB_KEY AS VARCHAR(100)
and used here: AND LOB_KEY IN (dbo.ufn_ParseString2Table(@LOB_KEY,',')) -- (@LOB_KEY)
 (See Below)

The stored procedure:

ALTER PROCEDURE [dbo].[sp_LossRunSummaryClaimantList]
	@SECURITY_ID AS VARCHAR(50), @ACCOUNT_NBR AS VARCHAR(40), @UNDERWRITING_PROGRAM_NBR AS VARCHAR(50), @CLAIM_STATUS AS VARCHAR(50), @LOB_KEY AS VARCHAR(100), @POLICY_YR AS INT  --@POLICY_YR AS INT
AS
BEGIN

-- EXEC [dbo].[sp_LMCClaimListAll5Year] 'S-1-5-21-3783409357-2204173064-303048338-183906', '0000011003', '0011'

	IF EXISTS (SELECT * FROM dbo.PORTAL_USER u JOIN dbo.PORTAL_USER_PERMISSION up ON up.USER_KEY = u.USER_KEY WHERE u.SECURITY_ID = @SECURITY_ID AND up.ACCOUNT_NBR IN (@ACCOUNT_NBR,'ALL') AND up.UNDERWRITING_PROGRAM_NBR = @UNDERWRITING_PROGRAM_NBR)
	BEGIN

		SELECT
				LineOfBusiness = LOB_NM,
				PolicyYear = POLICY_YR,
				ClaimStatus = CLAIM_LAST_STATUS,
				ClaimNumber = ISNULL(CLAIM_LEGACY_NBR, CLAIM_NBR),
				ClaimantNumber = CLAIMANT_NBR,
				ClaimantName = CLAIMANT_NM,
				LossDate = LOSS_DT,
				Paid = SUM(GROSS_LOSS_PAID + GROSS_EXPENSE_PAID) + SUM(WC_GROSS_PAID) ,
				Reserves = SUM(LOSS_RESERVE + EXPENSE_RESERVE) + SUM(WC_RESERVE) ,
				TotalIncurredAmount = SUM(GROSS_LOSS_PAID + GROSS_EXPENSE_PAID + LOSS_RESERVE + EXPENSE_RESERVE + SUBROGATION + SALVAGE + DEDUCTIBLE_RECOVERY + RECOVERIES_OTHER) +
				SUM(WC_GROSS_PAID + WC_RESERVE + WC_RECOVERIES),
				Recoveries = SUM(SUBROGATION + SALVAGE + DEDUCTIBLE_RECOVERY + RECOVERIES_OTHER) + SUM(WC_RECOVERIES)
		FROM dbo.AGG_MEMBER_CENTER
		WHERE ACCOUNT_NBR = @ACCOUNT_NBR
			AND UNDERWRITING_PROGRAM_NBR = @UNDERWRITING_PROGRAM_NBR
			AND LAST_STATUS IN (@CLAIM_STATUS) 
			AND LOB_KEY IN (dbo.ufn_ParseString2Table(@LOB_KEY,',')) -- (@LOB_KEY) 
			AND POLICY_YR IN (@POLICY_YR) --(dbo.ufn_ParseString2Table(@POLICY_YR,',')) -- (@POLICY_YR)
		GROUP BY LOB_NM,
				POLICY_YR,
				ISNULL(CLAIM_LEGACY_NBR, CLAIM_NBR),
				CLAIM_LAST_STATUS,
				CLAIMANT_NBR, 
				CLAIMANT_NM,
				LOSS_DT
		ORDER BY 1 ASC ,
				2 DESC,
				4 DESC;

	END

SQL Function that returns multi-select list:

USE [BRAC_Portal]
GO
/****** Object:  UserDefinedFunction [dbo].[ufn_ParseString2Table]    Script Date: 8/8/2016 1:48:53 PM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

ALTER FUNCTION [dbo].[ufn_ParseString2Table] (@String VARCHAR(8000), @Delimiter VARCHAR(10) = ',')
/************************************************************************
PROCEDURE 	uf_ManageSecurityFlag

	ARGUMENTS	
				
	RETURNS		Table in table variable

	DESCRIPTION RETRIEVES CURRENT USER INFO

	AUTHOR	DATE		DESCRIPTION
	DOL		08/8/2016	Parses Delimited String to Table

	EXAMPLE
	SELECT CONVERT(INT,ITEM) FROM dbo.ufn_ParseString2Table ('39, 549, 324, 3556, 24, 2132, 345 ,', ',')
************************************************************************/
RETURNS @ReturnTable TABLE(Item VARCHAR(100))
AS
BEGIN

	WHILE CHARINDEX(@Delimiter,@String)>0
	BEGIN
		INSERT @ReturnTable
		SELECT SUBSTRING(@String,1,(CHARINDEX(@Delimiter,@String)-1))
		SELECT @String=RIGHT(@String,DATALENGTH(@String)-CHARINDEX(@Delimiter,@String))
 
	END
	INSERT @ReturnTable SELECT @String
	
	RETURN 
END

Thanks,

Dan