diff --git a/science/mcpl/Makefile b/science/mcpl/Makefile
index 7ee2ca520278..25c22bb8a36c 100644
--- a/science/mcpl/Makefile
+++ b/science/mcpl/Makefile
@@ -1,27 +1,30 @@
 PORTNAME=	mcpl
 DISTVERSIONPREFIX=	v
 DISTVERSION=	2.2.0
 CATEGORIES=	science # physics
 
 MAINTAINER=	yuri@FreeBSD.org
 COMMENT=	Monte Carlo Particle Lists library
 WWW=		https://mctools.github.io/mcpl/ \
 		https://github.com/mctools/mcpl
 
 LICENSE=	APACHE20
 LICENSE_FILE=	${WRKSRC}/LICENSE
 
+NOT_FOR_ARCHS=	armv7 powerpc i386
+NOT_FOR_ARCHS_REASON=	MCPL does not support 32 bit platforms
+
 BROKEN_i386=	compilation fails, see https://github.com/mctools/mcpl/issues/88
 
 USES=		cmake:testing
 USE_LDCONFIG=	yes
 
 USE_GITHUB=	yes
 GH_ACCOUNT=	mctools
 
 CMAKE_OFF=	MCPL_ENABLE_TESTING
 CMAKE_TESTING_ON=	MCPL_ENABLE_TESTING
 
 # tests as of 2.2.0: 100% tests passed, 0 tests failed out of 32
 
 .include <bsd.port.mk>