diff --git a/src/distribution/dirichlet.rs b/src/distribution/dirichlet.rs
index 2670929a..355476db 100644
--- a/src/distribution/dirichlet.rs
+++ b/src/distribution/dirichlet.rs
@@ -369,15 +369,12 @@ where
 #[rustfmt::skip]
 #[cfg(test)]
 mod tests {
+    use super::*;
+
     use std::fmt::{Debug, Display};
 
     use nalgebra::{dmatrix, dvector, vector, DimMin, OVector};
 
-    use crate::{
-        distribution::{Continuous, Dirichlet},
-        statistics::{MeanN, VarianceN},
-    };
-
     fn try_create<D>(alpha: OVector<f64, D>) -> Dirichlet<D>
     where
         D: DimMin<D, Output = D>,
@@ -580,4 +577,10 @@ mod tests {
         let n = try_create(vector![0.1, 0.3, 0.5, 0.8]);
         n.ln_pdf(&vector![0.5, 0.25, 0.8, 0.9]);
     }
+
+    #[test]
+    fn test_error_is_sync_send() {
+        fn assert_sync_send<T: Sync + Send>() {}
+        assert_sync_send::<DirichletError>();
+    }
 }
diff --git a/src/distribution/internal.rs b/src/distribution/internal.rs
index c3b9f22c..9e7651b0 100644
--- a/src/distribution/internal.rs
+++ b/src/distribution/internal.rs
@@ -241,6 +241,13 @@ pub mod test {
                     )
                 }
             }
+
+            /// Asserts that associated error type is Send and Sync
+            #[test]
+            fn test_error_is_sync_send() {
+                fn assert_sync_send<T: Sync + Send>() {}
+                assert_sync_send::<$dist_err>();
+            }
         };
     }
 
diff --git a/src/distribution/multinomial.rs b/src/distribution/multinomial.rs
index aca82a2a..7d1b408c 100644
--- a/src/distribution/multinomial.rs
+++ b/src/distribution/multinomial.rs
@@ -500,6 +500,12 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_error_is_sync_send() {
+        fn assert_sync_send<T: Sync + Send>() {}
+        assert_sync_send::<MultinomialError>();
+    }
+
     //     #[test]
     //     #[should_panic]
     //     fn test_pmf_x_wrong_length() {
diff --git a/src/distribution/multivariate_normal.rs b/src/distribution/multivariate_normal.rs
index 68b8d098..eb86edd3 100644
--- a/src/distribution/multivariate_normal.rs
+++ b/src/distribution/multivariate_normal.rs
@@ -389,6 +389,8 @@ mod tests  {
         statistics::{Max, MeanN, Min, Mode, VarianceN},
     };
 
+    use super::MultivariateNormalError;
+
     fn try_create<D>(mean: OVector<f64, D>, covariance: OMatrix<f64, D, D>) -> MultivariateNormal<D>
     where
         D: DimMin<D, Output = D>,
@@ -703,4 +705,10 @@ mod tests  {
         let mvn = MultivariateNormal::new(vec![0., 0.], vec![1., 0., 0., 1.,]).unwrap();
         mvn.pdf(&vec![1.].into()); // x.size != mu.size
     }
+
+    #[test]
+    fn test_error_is_sync_send() {
+        fn assert_sync_send<T: Sync + Send>() {}
+        assert_sync_send::<MultivariateNormalError>();
+    }
 }
diff --git a/src/distribution/multivariate_students_t.rs b/src/distribution/multivariate_students_t.rs
index 8bcb1d78..b75e0a88 100644
--- a/src/distribution/multivariate_students_t.rs
+++ b/src/distribution/multivariate_students_t.rs
@@ -397,6 +397,8 @@ mod tests  {
         statistics::{Max, MeanN, Min, Mode, VarianceN},
     };
 
+    use super::MultivariateStudentError;
+
     fn try_create(location: Vec<f64>, scale: Vec<f64>, freedom: f64) -> MultivariateStudent<Dyn>
     {
         let mvs = MultivariateStudent::new(location, scale, freedom);
@@ -614,5 +616,9 @@ mod tests  {
         assert_eq!(mvs.scale_chol_decomp(), &OMatrix::<f64, Dyn, Dyn>::identity(2, 2));
     }
         
-    
+    #[test]
+    fn test_error_is_sync_send() {
+        fn assert_sync_send<T: Sync + Send>() {}
+        assert_sync_send::<MultivariateStudentError>();
+    }
 }