diff --git a/Makefile b/Makefile
index 2406f9352..7f5c4d68a 100644
--- a/Makefile
+++ b/Makefile
@@ -232,7 +232,7 @@ else
 		ifeq ($(COMPILER_NAME),NVHPC)
 			CXXFLAGS += -fast
 		else
-			CXXFLAGS += -ffast-math -funsafe-math-optimizations -fno-finite-math-only -fopenmp-simd
+			CXXFLAGS += -ffast-math -funsafe-math-optimizations -fno-finite-math-only
 		endif
 	endif
 endif
diff --git a/atomic.h b/atomic.h
index 4c0c58124..a4a86d613 100644
--- a/atomic.h
+++ b/atomic.h
@@ -58,7 +58,7 @@ inline auto get_nlevels(const int element, const int ion) -> int {
 }
 
 // Return the energy of (element,ion,level).
-#pragma omp declare simd
+
 [[nodiscard]] inline auto epsilon(const int element, const int ion, const int level) -> double {
   assert_testmodeonly(element < get_nelements());
   assert_testmodeonly(ion < get_nions(element));
@@ -120,7 +120,7 @@ inline auto get_nphixstargets(const int element, const int ion, const int level)
 }
 
 // Return the statistical weight of (element,ion,level).
-#pragma omp declare simd
+
 [[nodiscard]] inline auto stat_weight(const int element, const int ion, const int level) -> double {
   assert_testmodeonly(element < get_nelements());
   assert_testmodeonly(ion < get_nions(element));
diff --git a/ltepop.h b/ltepop.h
index 9d7d1c8e6..08dbe26ae 100644
--- a/ltepop.h
+++ b/ltepop.h
@@ -4,11 +4,11 @@
 #include <vector>
 
 [[nodiscard]] auto get_groundlevelpop(int nonemptymgi, int element, int ion) -> double;
-#pragma omp declare simd
+
 [[nodiscard]] auto calculate_levelpop(int nonemptymgi, int element, int ion, int level) -> double;
-#pragma omp declare simd
+
 [[nodiscard]] auto calculate_levelpop_lte(int nonemptymgi, int element, int ion, int level) -> double;
-#pragma omp declare simd
+
 [[nodiscard]] auto get_levelpop(int nonemptymgi, int element, int ion, int level) -> double;
 [[nodiscard]] auto calculate_sahafact(int element, int ion, int level, int upperionlevel, double T, double E_threshold)
     -> double;
diff --git a/macroatom.cc b/macroatom.cc
index 2bdc75ee4..c30766e5c 100644
--- a/macroatom.cc
+++ b/macroatom.cc
@@ -646,7 +646,7 @@ void macroatom_close_file() {
 
 // radiative deexcitation rate: paperII 3.5.2
 // multiply by upper level population to get a rate per second
-#pragma omp declare simd
+
 auto rad_deexcitation_ratecoeff(const int nonemptymgi, const int element, const int ion, const int lower,
                                 const double epsilon_trans, const float A_ul, const double upperstatweight,
                                 const double nnlevelupper, const double t_current) -> double {
@@ -690,7 +690,7 @@ auto rad_deexcitation_ratecoeff(const int nonemptymgi, const int element, const
 
 // radiative excitation rate: paperII 3.5.2
 // multiply by lower level population to get a rate per second
-#pragma omp declare simd
+
 auto rad_excitation_ratecoeff(const int nonemptymgi, const int element, const int ion, const int lower,
                               const int uptransindex, const double epsilon_trans, const double nnlevel_lower,
                               const int lineindex, const double t_current) -> double {
@@ -732,7 +732,7 @@ auto rad_excitation_ratecoeff(const int nonemptymgi, const int element, const in
 
 // radiative recombination rate: paperII 3.5.2
 // multiply by upper level population to get a rate per second
-#pragma omp declare simd
+
 auto rad_recombination_ratecoeff(const float T_e, const float nne, const int element, const int upperion,
                                  const int upperionlevel, const int lowerionlevel, const int nonemptymgi) -> double {
   // it's probably faster to only check this condition outside this function
@@ -777,7 +777,7 @@ auto stim_recombination_ratecoeff(const float nne, const int element, const int
 }
 
 // multiply by upper level population to get a rate per second
-#pragma omp declare simd
+
 auto col_recombination_ratecoeff(const float T_e, const float nne, const int element, const int upperion,
                                  const int upper, const int lower, const double epsilon_trans) -> double {
   // it's probably faster to only check this condition outside this function
@@ -818,7 +818,7 @@ auto col_recombination_ratecoeff(const float T_e, const float nne, const int ele
 
 // collisional ionization rate: paperII 3.5.1
 // multiply by lower level population to get a rate per second
-#pragma omp declare simd
+
 auto col_ionization_ratecoeff(const float T_e, const float nne, const int element, const int ion, const int lower,
                               const int phixstargetindex, const double epsilon_trans) -> double {
   assert_testmodeonly(phixstargetindex >= 0);
@@ -850,7 +850,7 @@ auto col_ionization_ratecoeff(const float T_e, const float nne, const int elemen
 }
 
 // multiply by upper level population to get a rate per second
-#pragma omp declare simd
+
 auto col_deexcitation_ratecoeff(const float T_e, const float nne, const double epsilon_trans, const int element,
                                 const int ion, const int upper, const LevelTransition &downtransition) -> double {
   const int lower = downtransition.targetlevelindex;
@@ -901,7 +901,7 @@ auto col_deexcitation_ratecoeff(const float T_e, const float nne, const double e
 }
 
 // multiply by lower level population to get a rate per second
-#pragma omp declare simd
+
 auto col_excitation_ratecoeff(const float T_e, const float nne, const int element, const int ion, const int lower,
                               const int uptransindex, const double epsilon_trans, const double lowerstatweight)
     -> double {
diff --git a/macroatom.h b/macroatom.h
index bee0939cc..69e13f6da 100644
--- a/macroatom.h
+++ b/macroatom.h
@@ -9,33 +9,29 @@ void macroatom_close_file();
 
 void do_macroatom(Packet &pkt, const MacroAtomState &pktmastate);
 
-#pragma omp declare simd
 [[nodiscard]] auto rad_deexcitation_ratecoeff(int nonemptymgi, int element, int ion, int lower, double epsilon_trans,
                                               float A_ul, double upperstatweight, double nnlevelupper, double t_current)
     -> double;
 
-#pragma omp declare simd
 [[nodiscard]] auto rad_excitation_ratecoeff(int nonemptymgi, int element, int ion, int lower, int uptransindex,
                                             double epsilon_trans, double nnlevel_lower, int lineindex, double t_current)
     -> double;
 
-#pragma omp declare simd
 [[nodiscard]] auto rad_recombination_ratecoeff(float T_e, float nne, int element, int upperion, int upperionlevel,
                                                int lowerionlevel, int nonemptymgi) -> double;
-#pragma omp declare simd
+
 [[nodiscard]] auto stim_recombination_ratecoeff(float nne, int element, int upperion, int upper, int lower,
                                                 int nonemptymgi) -> double;
 
-#pragma omp declare simd
 [[nodiscard]] auto col_recombination_ratecoeff(float T_e, float nne, int element, int upperion, int upper, int lower,
                                                double epsilon_trans) -> double;
-#pragma omp declare simd
+
 [[nodiscard]] auto col_ionization_ratecoeff(float T_e, float nne, int element, int ion, int lower, int phixstargetindex,
                                             double epsilon_trans) -> double;
-#pragma omp declare simd
+
 [[nodiscard]] auto col_deexcitation_ratecoeff(float T_e, float nne, double epsilon_trans, int element, int ion,
                                               int upper, const LevelTransition &downtransition) -> double;
-#pragma omp declare simd
+
 [[nodiscard]] auto col_excitation_ratecoeff(float T_e, float nne, int element, int ion, int lower, int uptransindex,
                                             double epsilon_trans, double lowerstatweight) -> double;
 
diff --git a/nonthermal.h b/nonthermal.h
index cb5455996..5218feb98 100644
--- a/nonthermal.h
+++ b/nonthermal.h
@@ -18,7 +18,7 @@ void solve_spencerfano(int nonemptymgi, int timestep, int iteration);
 void calculate_deposition_rate_density(int nonemptymgi, int timestep, HeatingCoolingRates &heatingcoolingrates);
 [[nodiscard]] auto get_deposition_rate_density(int nonemptymgi) -> double;
 [[nodiscard]] auto get_nt_frac_heating(int modelgridindex) -> float;
-#pragma omp declare simd
+
 [[nodiscard]] auto nt_excitation_ratecoeff(int nonemptymgi, int element, int ion, int lowerlevel, int uptransindex,
                                            int lineindex) -> double;
 void do_ntalpha_deposit(Packet &pkt);
diff --git a/radfield.cc b/radfield.cc
index 3b114c4d8..d834c3302 100644
--- a/radfield.cc
+++ b/radfield.cc
@@ -112,7 +112,7 @@ constexpr auto get_bin_nu_lower(const int binindex) -> double {
 }
 
 // find the left-closed bin [nu_lower, nu_upper) that nu belongs to
-#pragma omp declare simd
+
 constexpr auto select_bin(const double nu) -> int {
   if (nu < nu_lower_first_initial) {
     return -2;  // out of range, nu lower than lowest bin's lower boundary
@@ -224,7 +224,7 @@ void update_bfestimators(const int nonemptymgi, const double distance_e_cmf, con
                             globals::bfestim_nu_edge.data();
 
   const auto bfestimcount = globals::bfestimcount;
-#pragma omp simd
+
   for (auto bfestimindex = bfestimbegin; bfestimindex < bfestimend; bfestimindex++) {
     atomicadd(bfrate_raw[(nonemptymgi * bfestimcount) + bfestimindex],
               phixslist.gamma_contr[bfestimindex] * distance_e_cmf_over_nu);