diff --git a/datman/src/bin/datman.rs b/datman/src/bin/datman.rs
index 5bdba6f..df19d78 100644
--- a/datman/src/bin/datman.rs
+++ b/datman/src/bin/datman.rs
@@ -151,6 +151,7 @@ const PROGRESS_SPANS: &'static [&'static str] = &[
     "unpack_files",
     "expand_chunkrefs",
     "extract_files",
+    "check_all_chunks",
 ];
 
 #[tokio::main]
diff --git a/yama/src/bin/yama.rs b/yama/src/bin/yama.rs
index ad91350..faa217f 100644
--- a/yama/src/bin/yama.rs
+++ b/yama/src/bin/yama.rs
@@ -276,6 +276,7 @@ const PROGRESS_SPANS: &'static [&'static str] = &[
     "unpack_files",
     "expand_chunkrefs",
     "extract_files",
+    "check_all_chunks",
 ];
 
 #[tokio::main]
@@ -826,9 +827,6 @@ async fn main() -> eyre::Result<()> {
             if pointers {
                 bail!("pointers check not implemented yet. Try -2");
             }
-            if intensive {
-                bail!("intensive check not implemented yet. Try -2");
-            }
 
             let pile_connector_path = Path::new(".");
             let keyring = pre_open_keyring(&pile_connector_path).await?;
@@ -851,6 +849,14 @@ async fn main() -> eyre::Result<()> {
                     .context("shallow check failed")?;
             }
 
+            if intensive {
+                let all_bloblogs = pwc.localcache.read().await?.list_bloblogs().await?;
+
+                check::check_all_chunks_in_bloblogs(&pwc, &all_bloblogs)
+                    .await
+                    .context("intensive check failed")?;
+            }
+
             Arc::try_unwrap(pwc)
                 .map_err(|_| eyre!("pwc still in use; can't close down gracefully"))?
                 .close()
diff --git a/yama/src/check.rs b/yama/src/check.rs
index 7b08197..f953b32 100644
--- a/yama/src/check.rs
+++ b/yama/src/check.rs
@@ -1,12 +1,20 @@
 use crate::extract::expand_chunkrefs;
 use crate::pile_with_cache::PileWithCache;
-use eyre::{bail, ContextCompat};
-use std::collections::BTreeSet;
+use crate::retriever::decompressor::DECOMPRESS_CAPACITY;
+use crate::PROGRESS_BAR_STYLE;
+use eyre::{bail, eyre, Context, ContextCompat};
+use flume::{Receiver, Sender};
+use indicatif::ProgressStyle;
+use std::collections::{BTreeMap, BTreeSet};
 use std::sync::Arc;
-use tracing::info;
+use tokio::task::JoinSet;
+use tracing::{error, info, info_span, Instrument, Span};
+use tracing_indicatif::span_ext::IndicatifSpanExt;
 use yama_midlevel_crypto::chunk_id::ChunkId;
+use yama_pile::definitions::BloblogId;
 use yama_pile::tree::TreeNode;
 use yama_wormfile::boxed::BoxedWormFileProvider;
+use zstd::bulk::Decompressor;
 
 /// Check that all pointers point to chunks that exist **in our local cache**.
 pub async fn check_pointers_point_to_indexed_chunks(
@@ -62,3 +70,154 @@ pub async fn check_pointers_point_to_indexed_chunks(
 
     Ok(())
 }
+
+/// Checks all the chunks in the bloblog and then returns the number of chunks that were checked.
+pub async fn check_all_chunk_hashes_in_bloblog(
+    pwc: &Arc<PileWithCache<BoxedWormFileProvider>>,
+    bloblog_id: BloblogId,
+) -> eyre::Result<u64> {
+    let mut decompressor = match &pwc.pile.pile_config.zstd_dict {
+        Some(dict) => Decompressor::with_dictionary(dict)?,
+        None => Decompressor::new()?,
+    };
+    let chunk_id_key = &pwc.pile.pile_config.chunk_id_key;
+
+    let mut bloblog = pwc
+        .pile
+        .read_bloblog(bloblog_id)
+        .await
+        .with_context(|| format!("could not open bloblog for checking: {bloblog_id:?}"))?;
+    let offsets_and_chunks_to_read: BTreeMap<u64, ChunkId> = bloblog
+        .footer()
+        .chunks
+        .iter()
+        .map(|(chunk_id, locator)| (locator.offset, *chunk_id))
+        .collect();
+
+    let mut buf = Vec::with_capacity(DECOMPRESS_CAPACITY);
+
+    let mut checked = 0;
+
+    for (_, chunk_id) in offsets_and_chunks_to_read {
+        let blob = bloblog
+            .read_chunk(chunk_id)
+            .await?
+            .context("missing chunk")?;
+
+        (decompressor, buf) = tokio::task::spawn_blocking(move || {
+            decompressor
+                .decompress_to_buffer(&blob, &mut buf)
+                .with_context(|| format!("failed to decompress {chunk_id:?} in {bloblog_id:?}"))?;
+            Ok::<_, eyre::Error>((decompressor, buf))
+        })
+        .await??;
+
+        if !chunk_id.verify(&buf, chunk_id_key) {
+            bail!("verification failure: chunk {chunk_id:?} in bloblog {bloblog_id:?} is corrupt!");
+        }
+
+        checked += 1;
+    }
+
+    Ok(checked)
+}
+
+pub async fn check_all_chunks_in_bloblogs(
+    pwc: &Arc<PileWithCache<BoxedWormFileProvider>>,
+    bloblogs: &BTreeSet<BloblogId>,
+) -> eyre::Result<()> {
+    let prog_span = info_span!("check_all_chunks");
+    async {
+        let prog_span = Span::current();
+        prog_span.pb_set_style(
+            &ProgressStyle::default_bar()
+                .template(PROGRESS_BAR_STYLE)
+                .unwrap(),
+        );
+        prog_span.pb_set_length(bloblogs.len() as u64);
+        prog_span.pb_set_message("checking all bloblogs");
+
+        let mut workers = JoinSet::new();
+
+        let (bloblog_id_tx, bloblog_id_rx) = flume::bounded(16);
+        let (progress_tx, progress_rx) = flume::bounded(16);
+
+        for _ in 0..4 {
+            let pwc = pwc.clone();
+            let bloblog_id_rx = bloblog_id_rx.clone();
+            let progress_tx = progress_tx.clone();
+            workers.spawn(async {
+                if let Err(err) =
+                    check_all_chunks_in_bloblogs_worker(pwc, bloblog_id_rx, progress_tx).await
+                {
+                    error!("Error in chunk checker worker: {err:?}")
+                }
+            });
+        }
+
+        drop(progress_tx);
+        drop(bloblog_id_rx);
+
+        let mut success = true;
+        let mut num_bloblogs_outstanding = bloblogs.len();
+        let mut total_chunks_checked = 0u64;
+
+        tokio::join!(
+            async move {
+                for bloblog_id in bloblogs {
+                    bloblog_id_tx
+                        .send_async(*bloblog_id)
+                        .await
+                        .expect("can no longer submit new bloblogs to be checked; fault?");
+                }
+                drop(bloblog_id_tx);
+            },
+            async {
+                while let Ok(res) = progress_rx.recv_async().await {
+                    match res {
+                        Ok(chunks_checked) => {
+                            total_chunks_checked += chunks_checked;
+                        }
+                        Err(err) => {
+                            error!("check failure: {err:?}");
+                            success = false;
+                        }
+                    }
+                    prog_span.pb_inc(1);
+                    num_bloblogs_outstanding = num_bloblogs_outstanding
+                        .checked_sub(1)
+                        .expect("more bloblogs progress reports than expected?");
+                }
+            }
+        );
+
+        if num_bloblogs_outstanding > 0 {
+            bail!("{num_bloblogs_outstanding} bloblogs outstanding somehow");
+        }
+
+        info!("{total_chunks_checked} chunks checked!");
+
+        if !success {
+            bail!("There were chunk check failures.");
+        }
+
+        Ok(())
+    }
+    .instrument(prog_span)
+    .await
+}
+
+pub async fn check_all_chunks_in_bloblogs_worker(
+    pwc: Arc<PileWithCache<BoxedWormFileProvider>>,
+    bloblogs_rx: Receiver<BloblogId>,
+    progress_tx: Sender<eyre::Result<u64>>,
+) -> eyre::Result<()> {
+    while let Ok(bloblog_id) = bloblogs_rx.recv_async().await {
+        let check = check_all_chunk_hashes_in_bloblog(&pwc, bloblog_id).await;
+        progress_tx
+            .send_async(check)
+            .await
+            .map_err(|_| eyre!("check progress tx shut down"))?;
+    }
+    Ok(())
+}
diff --git a/yama_localcache/src/lib.rs b/yama_localcache/src/lib.rs
index 3f372df..b7e9f36 100644
--- a/yama_localcache/src/lib.rs
+++ b/yama_localcache/src/lib.rs
@@ -337,6 +337,21 @@ impl<const RW: bool> StoreConnection<RW> {
         row_results.into_iter().collect()
     }
 
+    pub async fn list_bloblogs(&mut self) -> eyre::Result<BTreeSet<BloblogId>> {
+        let row_results = query!(
+            "
+            SELECT bloblog_sha256 FROM bloblogs
+        "
+        )
+        .map(|row| {
+            BloblogId::try_from(row.bloblog_sha256.as_ref())
+                .context("failed to decode BloblogId in local cache")
+        })
+        .fetch_all(&mut *self.conn)
+        .await?;
+        row_results.into_iter().collect()
+    }
+
     pub async fn is_chunk_new(&mut self, chunk_id: ChunkId) -> eyre::Result<bool> {
         let chunk_id_text = chunk_id.to_string();
         let is_new = query!(
diff --git a/yama_pile/src/bloblogs.rs b/yama_pile/src/bloblogs.rs
index 0a37247..a3c8d28 100644
--- a/yama_pile/src/bloblogs.rs
+++ b/yama_pile/src/bloblogs.rs
@@ -211,4 +211,8 @@ impl<R: WormFileReader + Unpin> BloblogReader<R> {
             None => Ok(None),
         }
     }
+
+    pub fn footer(&self) -> &BloblogFooter {
+        &self.footer
+    }
 }