diff --git a/.gitignore b/.gitignore
index b2c18337..837d4992 100644
--- a/.gitignore
+++ b/.gitignore
@@ -100,8 +100,8 @@ celerybeat-schedule
 # Environments
 .env
 .venv
-env/
-venv/
+env*/
+venv*/
 ENV/
 env.bak/
 venv.bak/
diff --git a/pytissueoptics/rayscattering/__init__.py b/pytissueoptics/rayscattering/__init__.py
index fc012536..8ab8c01e 100644
--- a/pytissueoptics/rayscattering/__init__.py
+++ b/pytissueoptics/rayscattering/__init__.py
@@ -15,7 +15,7 @@
 )
 from .energyLogging import EnergyLogger
 from .materials import ScatteringMaterial
-from .opencl import CONFIG, hardwareAccelerationIsAvailable
+from .opencl import CONFIG, disableOpenCL, hardwareAccelerationIsAvailable
 from .photon import Photon
 from .scatteringScene import ScatteringScene
 from .source import DirectionalSource, DivergentSource, IsotropicPointSource, PencilPointSource
@@ -49,6 +49,7 @@
     "View2DSliceZ",
     "samples",
     "Stats",
+    "disableOpenCL",
     "hardwareAccelerationIsAvailable",
     "CONFIG",
 ]
diff --git a/pytissueoptics/rayscattering/opencl/__init__.py b/pytissueoptics/rayscattering/opencl/__init__.py
index 703e0ee8..71a92eb3 100644
--- a/pytissueoptics/rayscattering/opencl/__init__.py
+++ b/pytissueoptics/rayscattering/opencl/__init__.py
@@ -1,5 +1,6 @@
 from pytissueoptics.rayscattering.opencl.config.CLConfig import OPENCL_AVAILABLE, WEIGHT_THRESHOLD, CLConfig, warnings
 from pytissueoptics.rayscattering.opencl.config.IPPTable import IPPTable
+import os
 
 OPENCL_OK = True
 
@@ -14,8 +15,17 @@
     CONFIG = None
 
 
+def disableOpenCL():
+    os.environ["PTO_DISABLE_OPENCL"] = "1"
+    print("You can define PTO_DISABLE_OPENCL=1 in your profile to avoid this call.")
+
+
 def validateOpenCL() -> bool:
     notAvailableMessage = "Error: Hardware acceleration not available. Falling back to CPU. "
+
+    if os.environ.get("PTO_DISABLE_OPENCL", "0") == "1":
+        warnings.warn("User requested not to use OpenCL with environment variable 'PTO_DISABLE_OPENCL'=1.")
+        return False
     if not OPENCL_AVAILABLE:
         warnings.warn(notAvailableMessage + "Please install pyopencl.")
         return False
@@ -28,7 +38,8 @@ def validateOpenCL() -> bool:
 
 
 def hardwareAccelerationIsAvailable() -> bool:
-    return OPENCL_AVAILABLE and OPENCL_OK
+    OPENCL_DISABLED = os.environ.get("PTO_DISABLE_OPENCL", "0") == "1"
+    return OPENCL_AVAILABLE and OPENCL_OK and not OPENCL_DISABLED
 
 
 __all__ = ["IPPTable", "WEIGHT_THRESHOLD"]