diff --git a/Source/Hydro/CAMR_construct_hydro_source.cpp b/Source/Hydro/CAMR_construct_hydro_source.cpp
index 7be65b7..c749735 100644
--- a/Source/Hydro/CAMR_construct_hydro_source.cpp
+++ b/Source/Hydro/CAMR_construct_hydro_source.cpp
@@ -104,12 +104,14 @@ CAMR::construct_hydro_source (const MultiFab& S,
             BL_PROFILE_VAR("ctoprim()", ctop);
             const Real small_num        = CAMRConstants::small_num;
             const Real dual_energy_eta  = CAMR::dual_energy_eta1;
+            int l_allow_negative_energy = CAMR::allow_negative_energy;
             ParallelFor(
               qbx, [=] AMREX_GPU_DEVICE(int i, int j, int k) noexcept {
 #ifdef AMREX_USE_EB
                 if (!flag_arr(i,j,k).isCovered()) {
 #endif
-                    hydro_ctoprim(i, j, k, sarr, qarr, qauxar, *lpmap, small_num, dual_energy_eta);
+                    hydro_ctoprim(i, j, k, sarr, qarr, qauxar, *lpmap,
+                                  small_num, dual_energy_eta, l_allow_negative_energy);
 #ifdef AMREX_USE_EB
                 } else {
                    for (int n=0; n<QVAR; n++) qarr(i,j,k,n) = 0.;
diff --git a/Source/Hydro/Hydro_ctoprim.H b/Source/Hydro/Hydro_ctoprim.H
index 832aa8e..1667914 100644
--- a/Source/Hydro/Hydro_ctoprim.H
+++ b/Source/Hydro/Hydro_ctoprim.H
@@ -16,8 +16,9 @@ hydro_ctoprim(
   amrex::Array4<      amrex::Real> const& q,
   amrex::Array4<      amrex::Real> const& qa,
   PassMap const& pmap,
-  amrex::Real small_num,
-  amrex::Real dual_energy_eta1)
+  amrex::Real l_small_num,
+  amrex::Real l_dual_energy_eta1,
+  const int l_allow_negative_energy)
 {
     const amrex::Real rho = u(i, j, k, URHO);
 
@@ -51,9 +52,11 @@ hydro_ctoprim(
          // of the separately updated internal energy equation.
          // Otherwise, we'll set e = E - K.
 
-        AMREX_ALWAYS_ASSERT(u(i,j,k,UEDEN) > 0.);
+        if (!l_allow_negative_energy) {
+            AMREX_ALWAYS_ASSERT(u(i,j,k,UEDEN) > 0.);
+        }
 
-        if ( (u(i,j,k,UEDEN) - kineng) / u(i,j,k,UEDEN) > dual_energy_eta1) {
+        if ( (u(i,j,k,UEDEN) - kineng) / u(i,j,k,UEDEN) > l_dual_energy_eta1) {
            q(i,j,k,QREINT) = (u(i,j,k,UEDEN) - kineng) * rhoinv;
         } else {
            q(i,j,k,QREINT) = u(i,j,k,UEINT) * rhoinv;
@@ -61,7 +64,9 @@ hydro_ctoprim(
 
         const amrex::Real e = q(i,j,k,QREINT);
 
-        AMREX_ALWAYS_ASSERT(u(i,j,k,UEINT) > 0.);
+        if (!l_allow_negative_energy) {
+            AMREX_ALWAYS_ASSERT(u(i,j,k,UEINT) > 0.);
+        }
 
         amrex::Real T = u(i, j, k, UTEMP);
         amrex::Real massfrac[NUM_SPECIES];
@@ -91,7 +96,7 @@ hydro_ctoprim(
         qa(i, j, k, QGAMC) = gam1;
         cs =  std::sqrt(gam1*p/rho);
         qa(i, j, k, QC) = cs;
-        qa(i, j, k, QCSML) = std::max(small_num, small_num * cs);
+        qa(i, j, k, QCSML) = std::max(l_small_num, l_small_num * cs);
     }
 }
 
diff --git a/Source/Params/_cpp_parameters b/Source/Params/_cpp_parameters
index 9904fab..f2e1ea3 100644
--- a/Source/Params/_cpp_parameters
+++ b/Source/Params/_cpp_parameters
@@ -91,7 +91,7 @@ dual_energy_eta2             Real          1.0e-4
 use_pslope                   int           0
 
 # Whether or not to allow internal energy to be less than zero
-allow_negative_energy        int           1
+allow_negative_energy        int           0
 
 # Whether or not to allow the internal energy to be less than the
 # internal energy corresponding to small\_temp
diff --git a/Source/Params/param_includes/CAMR_defaults.H b/Source/Params/param_includes/CAMR_defaults.H
index 7c6cb1f..3b450e2 100644
--- a/Source/Params/param_includes/CAMR_defaults.H
+++ b/Source/Params/param_includes/CAMR_defaults.H
@@ -24,7 +24,7 @@ int CAMR::dual_energy_update_E_from_e = 1;
 amrex::Real CAMR::dual_energy_eta1 = 1.0e0;
 amrex::Real CAMR::dual_energy_eta2 = 1.0e-4;
 int CAMR::use_pslope = 0;
-int CAMR::allow_negative_energy = 1;
+int CAMR::allow_negative_energy = 0;
 int CAMR::allow_small_energy = 1;
 int CAMR::transverse_reset_density = 1;
 int CAMR::eb_weights_type = 2;