diff --git a/R/tax_bill.R b/R/tax_bill.R
index 6d6f2b2..97a0eef 100644
--- a/R/tax_bill.R
+++ b/R/tax_bill.R
@@ -156,7 +156,7 @@ tax_bill <- function(year_vec,
     on = .(year, pin),
     c("av", "eav", "class", "exe_total") := .(
       i.av, i.eav, i.class,
-      rowSums(data.table::as.data.table(mget(exe_cols)))
+      rowSums(data.table::as.data.table(mget(exe_cols, inherits = TRUE)))
     )
   ]
   dt[class == "239", eav := av] # farmland is taxed on AV, not EAV