The morning of August 22, 1986, seemed like just another quiet morning beside Lake Nyos in northwest Cameroon. Ephriam Che, a farmer with four children, walked from his home down to the neighboring village. At first everything seemed normal, but it was unusually quiet. No birds sang, no insects buzzed. The normally blue waters of the lake had turned a muddy red, and the stream that usually flowed out of the lake was dry.

Ephraim realized something was wrong. He ran toward the village of Lower Nyos and discovered a horrific scene. Bodies of men, women, and children, as well as animals, were scattered around the village. Some looked as if they were trying to escape, while others had died in their beds. Some survivors woke up and discovered that every other member of their family had died.

The Danger Underneath

Over the next several weeks, medical and relief personnel poured into the areas surrounding Lake Nyos to care for the survivors. Around 1,800 people and over 3,000 animals died in the disaster, and at first no one knew why. By talking with the surviving villagers and taking measurements from the lake, scientists were able to form a good idea of what had happened at around 9 pm on August 21.

Ephraim reported hearing a rumbling sound before he went to bed that night. Halima Suley, who lived on the lake shore, heard the same rumbling, and also felt a strong wind rush through her family’s small huts right before she passed out. Tragically, she awoke to find that several of her children had died while she was unconscious.

Lake Nyos was located in a volcanic region, and for hundreds of years volcanic gases such as carbon dioxide and hydrogen sulfide seeped through the rock and built up in the deep and cold waters of the lake. The rumbling sound Ephraim heard was likely a landslide on one side of the lake that caused the warmer water in the top layer of the lake to mix with the colder water in the bottom layer that was saturated with large quantities of gas.

The mixing of the water in the lake caused the carbon dioxide to gush out of the water, a little like what happens when you remove the cap from a shaken bottle of soda. These gases are denser than air, causing them to stay near the ground and spill down over the villages surrounding the lake, suffocating nearly two thousand people in just minutes. The wind Halima had felt was a wall of invisible carbon dioxide rushing through her village.

The gases had apparently built up for hundreds of years, becoming more and more dangerous with no one realizing the danger. Then in less than an hour, many people died without knowing what had happened.

The Danger Within

A lake full of dissolved carbon dioxide is a dangerous thing, but within each of us is something far more deadly. Our hearts are hidden, just like the dissolved gases deep within the lake. If we allow them, bitterness and sin can build up inside us until they spill out onto others.

God warned Moses of the danger of bitter and poisonous souls hidden within the Israelites.

Beware lest there be among you a man or woman or clan or tribe whose heart is turning away today from the LORD our God to go and serve the gods of those nations. Beware lest there be among you a root bearing poisonous and bitter fruit, one who, when he hears the words of this sworn covenant, blesses himself in his heart, saying, ‘I shall be safe, though I walk in the stubbornness of my heart.’

Deuteronomy 29:18-19 (ESV)

We still must deal with the same bitterness and sinful desires that the children of Israel dealt with thousands of years ago. The gods of their day were Baal, Ashtoreth, and Molech; today we have the gods of individualism, materialism, and pleasure. If we unwittingly serve these gods, we are no safer than the one in Deuteronomy who thinks he is right with God, even though he is really following his own sinful heart.

We are not the only ones affected by our bitter and sinful hearts. Like the poisonous gases from deep within Lake Nyos, there can be many spiritual casualties when sin and bitterness spew from a single sinful heart. How many church issues are caused by only a few individuals with bitter hearts? How many relationships become toxic because of a few gossipers and busybodies who tear others down instead of building them up? A poisonous spirit can suffocate and kill many unwitting brothers and sisters.

God’s Solution

In the years following the Lake Nyos disaster, scientists discovered that dissolved gases were building up in the lake again. To prevent another disaster, they installed a pipe on the surface that reached nearly to the bottom of the lake. This pipe slowly released the gases in the lake so they wouldn’t build up and erupt again.

What can we do to prevent bitterness and sin from killing souls? During the time of the Judges, if the people worshipped the gods of the surrounding nations, the groves and altars could be destroyed. Today, the altars to our false gods are within our hearts, hidden but still deadly. With help from the Holy Spirit and our brothers and sisters in Christ, we can root out our hidden idols and turn back to the Lord.

We are often blind to our faults. For this reason we depend on diligent brothers and sisters to point out areas in which we should repent. This also goes the other way. We must know our brothers and sisters well enough that we can see when there is a “root of bitterness” within their hearts. We must also be willing to encourage and strengthen the weak brother or sister, not just for their souls, but for the many souls they influence.

Lake Nyos hadn’t erupted in living memory, but Ephraim Che’s ancestors had passed down myths over hundreds of years, warning that the waters Lake Nyos harbored destruction. Their traditions told them to build their homes in higher areas to protect themselves from the danger in the lake. Newcomers from other parts of Africa didn’t have the same traditions, and so built their homes in low-lying areas where the deadly gases gathered. The ones who had followed the tradition of building on high ground were spared from a danger they had never seen and didn’t understand.

Today we have something much greater; the teachings from God’s Word. We have the Ten Commandments, we have the teachings of Christ recorded in the Gospels, what more do we need? The issue is not that we need more teaching, but that we must act. We must realize the danger hidden within of our own sinful hearts and turn away from our idols to the Lord. We must diligently seek the direction and conviction of the Holy Spirit by spending time praying and reading the Word. We must look out for both ourselves and our brothers and sisters. “See to it that no one fails to obtain the grace of God; that no ‘root of bitterness’ springs up and causes trouble, and by it many become defiled.” (Hebrews 12:15)