"This is the hardest post I will ever have to write, but this information needs to be shared," she began.
She said news reports had claimed her youngest of three sons had fallen off the dock and drowned; but she knew from the moment it happened this was not the case — Andrew had grown up on the water and was a very strong swimmer, but had not even struggled after falling in.
After an autopsy, doctors found the boy's COHb levels were 72 percent: "His so-called 'drowning' was secondary to the fact that he would have never lived at that level," his mother wrote.
She said Andrew had spent most of the the day sat at the back of their open-topped Malibu Skier.
"Boats, even moving, create a backdraft of exhaust," she wrote, "carbon monoxide exits the rear of the boat and drafts right back into the back of the boat. Backseat riders are especially vulnerable at low speeds and in long no-wake zones like the one we had to cross to return to the docks."
"Our little Andy, our Dude, was probably slowly dying that afternoon/evening and we didn’t know it," she said, adding that any headache or tiredness would have been attributed to too much sun coupled with the long day of wakeboarding, wake surfing and tubing.
Andrew, she said, had crawled up onto the back edge of the boat while the family were packing at the dock, before he fell unconscious, "unaware of his impending death."
"We had no idea anything unusual was taking place," Cassandra wrote.
At that stage, his blood was at 72 percent, or 720,000 parts per million carbon monoxide, and no longer capable of carrying oxygen.
"Had he not fallen over, had he made it into the car, even if he wouldn't have passed at the lake, he would’ve been so severely brain-damaged that he likely would've passed away in his sleep on the way home," she said. "Even if he would’ve gone immediately to the ER at that time, he still would've died. No medicine could've saved him at his levels. There was nothing that could've been done at this point."
The distraught mother said the family took a little solace in knowing their was nothing they could have done at the time of his death.
"He did not suffer - he fell asleep," she wrote "I've been assured that my baby was so far gone that he did not cry out for me in his mind as he died. He went to sleep and that was it."
The heartbroken mother issued a warning to all boaters of the risks she says are downplayed or ignored by those in authority.
She said that road and air vehicles have to abide by far stricter registration codes, and that statistics on open-air carbon monoxide poisonings on water craft are skewed, because fatalities are usually attributed — as her son's almost was — to drowning, or heart failure.
She claimed boat manufacturers are aware of the risks and have addressed the issue on newer models; however they are under no obligation to retrofit older models or even make people who buy used watercraft aware of the dangers.
"It may be a one-in-a-million chance, but it exists," she wrote. "It happens in minutes- sometimes within 60 seconds."
Andy, who was smaller than his older brothers, had been moving around the boat less than them on the fateful day; nevertheless his older siblings still had to be treated for carbon monoxide poisoning in the hospital the day he died.
"We could've lost all three of our children that night. As hard as it is to swallow, we were fortunate," she wrote. "Fortunate that Andy doesn't have to spend his life on life support. Fortunate that his brothers lived."
"Don't let Andy's death be in vain," she concluded. "Educate yourself and educate your friends and family. I do not want anyone else to ever experience what I am going through."