diff --git a/README.md b/README.md
index d212717..30aaa36 100644
--- a/README.md
+++ b/README.md
@@ -347,9 +347,11 @@ added.
 ### Testing Requirements
 
 - Docker Desktop installed, either of the Linux or Windows runtimes, doesn't matter
-- pytest
-- hypothesis
-- pytest-cov (coverage.py)
+- Python packages:
+  - `docker`
+  - `hypothesis`
+  - `pytest`
+  - `pytest-cov` (coverage.py)
 
 ### What Is Tested?
 
diff --git a/bcpandas/main.py b/bcpandas/main.py
index 4b94801..52eb22a 100644
--- a/bcpandas/main.py
+++ b/bcpandas/main.py
@@ -348,7 +348,7 @@ def to_sql(
     batch_size: Optional[int] = None,
     use_tablock: bool = False,
     debug: bool = False,
-    bcp_path: Optional[str] = None,
+    bcp_path: Optional[Union[str, Path]] = None,
     dtype: Optional[dict] = None,
     process_dest_table: bool = True,
     print_output: bool = True,
@@ -358,6 +358,7 @@ def to_sql(
     work_directory: Optional[Path] = None,
     collation: str = sql_collation,
     identity_insert: bool = False,
+    err_file: Optional[Union[str, Path]] = None,
 ):
     """
     Writes the pandas DataFrame to a SQL table or view.
@@ -396,7 +397,7 @@ def to_sql(
         Setting this option allows for larger batch sizes.
     debug : bool, default False
         If True, will not delete the temporary CSV and format files, and will output their location.
-    bcp_path : str, default None
+    bcp_path : str, pathlib.Path, default None
         The full path to the BCP utility, useful if it is not in the PATH environment variable
     dtype: dict, default None
         A dict with keys the names of columns and values SqlAlchemy types for defining their types. These are
@@ -420,6 +421,10 @@ def to_sql(
         system-default for temporary files.
     identity_insert: bool, default False
         Specifies that identity value or values in the imported data file are to be used for the identity column.
+    err_file: str, pathlib.Path, default None
+        Specifies the full path of an error file used to store any rows that the bcp utility can't transfer from
+        the file to the database. Error messages from the bcp command go to the workstation of the user.
+        If this option isn't used, an error file isn't created.
 
     Notes
     -----
@@ -505,6 +510,7 @@ def to_sql(
             use_tablock=use_tablock,
             bcp_path=bcp_path,
             identity_insert=identity_insert,
+            err_file=err_file,
         )
     finally:
         if not debug:
diff --git a/bcpandas/utils.py b/bcpandas/utils.py
index 5b3250f..3229883 100644
--- a/bcpandas/utils.py
+++ b/bcpandas/utils.py
@@ -52,6 +52,7 @@ def bcp(
     row_terminator: Optional[str] = None,
     bcp_path: Optional[Union[str, Path]] = None,
     identity_insert: bool = False,
+    err_file: Optional[Union[str, Path]] = None,
 ):
     """
     See https://docs.microsoft.com/en-us/sql/tools/bcp-utility
@@ -116,6 +117,9 @@ def bcp(
     if identity_insert:
         bcp_command += ["-E"]
 
+    if err_file:
+        bcp_command += ["-e", str(err_file)]
+
     # formats
     if direc == IN and format_file_path is not None:
         bcp_command += ["-f", str(format_file_path)]
diff --git a/tests/test_to_sql.py b/tests/test_to_sql.py
index c7c9b9e..88a61ab 100644
--- a/tests/test_to_sql.py
+++ b/tests/test_to_sql.py
@@ -322,6 +322,43 @@ def test_custom_work_directory(sql_creds):
         assert conn.exec_driver_sql("SELECT * FROM some_table").first()[0] == 1.5
 
 
+def test_identity_insert_param(sql_creds):
+    """
+    Test ingest is successful when identity_insert param used.
+    """
+    to_sql(
+        df=pd.DataFrame({"col1": [1.5]}),
+        table_name="some_table",
+        creds=sql_creds,
+        if_exists="replace",
+        index=False,
+        sql_type="table",
+        identity_insert=True,
+    )
+    with sql_creds.engine.connect() as conn:
+        assert conn.exec_driver_sql("SELECT * FROM some_table").first()[0] == 1.5
+
+
+def test_custom_err_file(sql_creds):
+    """
+    Test the err_file parameters.
+    """
+    err_file = Path(__file__).parent.joinpath("err_file.log")
+    to_sql(
+        df=pd.DataFrame({"col1": [pd.Timedelta(days=1)]}),
+        table_name="some_table",
+        creds=sql_creds,
+        if_exists="replace",
+        index=False,
+        sql_type="table",
+        err_file=err_file,
+    )
+    with open(err_file) as f:
+        assert "Invalid character value for cast specification" in f.read()
+
+    err_file.unlink(missing_ok=True)
+
+
 @pytest.mark.usefixtures("database")
 class _BaseToSql:
     sql_type = "table"
diff --git a/tests/utils.py b/tests/utils.py
index df1c38d..3c2e853 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -135,11 +135,13 @@ def __init__(
 
     def start(self):
         if not self.accept_eula:
-            raise ValueError("Must accept Microsft's End User License Agreement")
+            raise ValueError("Must accept Microsoft's End User License Agreement")
+
         env = {
             "ACCEPT_EULA": "Y",
             "SA_PASSWORD": self.sa_sql_password,
         }
+
         if self.mssql_image.startswith("mcr.microsoft.com/mssql/server"):
             # means it's linux
             env["MSSQL_PID"] = self.mssql_pid