Scientists criticize practices of shuttered Portland carbon-capturing company [Video]

The Portland-based ocean carbon capture startup that shut down suddenly on Friday after gaining international praise is being criticized for dubious scientific claims and practices.

Running Tide purported to deploy chunks of wood waste coated in limestone and kelp spores into the ocean near Iceland, where they would absorb carbon and sink to the seabed or be eaten by marine animals. The startup would then sell carbon credits to big companies such as Microsoft and the ecommerce platform Shopify to offset their emissions.

CEO Marty Odlin said Running Tide, which had over 120 employees at its peak and raised more than $50 million from private investors, closed because it could no longer sell enough carbon credits to survive after the market collapsed last fall. Analysts attributed the collapse to questions about the environmental impact of carbon credits and the integrity of projects claiming to offset carbon emissions.

A three-month investigationpublished Friday by the Icelandic newspaper Heimildin found that Running Tide didn’t deploy …