SACRAMENTO - The California Air Resources Board has fined three international shipping companies a combined $440,250 for failure to switch from dirty "bunker" fuel to cleaner, low-sulfur marine distillate fuel upon entering Regulated California Waters, as required by state law.

"Ships en route to California ports emit thousands of tons of diesel exhaust each year," said ARB Enforcement Chief Jim Ryden. "Our regulation requiring ocean-going vessels to switch to cleaner fuel within 24 nautical miles of our shoreline protects all California residents, especially those in port communities, from this air pollution."

An ARB investigation showed that on 17 visits to California ports between November 6, 2009 and July 18, 2011, the vessel Hoegh Inchon operated its main engines within Regulated California Waters on bunker fuel, a dirtier fuel oil that contributes to onshore pollution levels of diesel particulate matter, sulfur oxides and nitrogen oxides. The parent company, Hoegh Autoliners Shipping AS Co. of Oslo, Norway, was fined $299,500.

In February 2013, prior to docking at the Ports of Stockton and Long Beach, the Ikan Bawal was cited for failing to switch its engines over to the required cleaner fuel while operating within Regulated California Waters. Its owner, N.C.N Corporation Panama, was fined $87,750.

In August 2012, after it docked at the Port of Los Angeles, the vessel K-Pluto was also cited for failing to switch to the required cleaner fuel while operating within Regulated California Waters. Its parent company, Twin Phoenix Shipping S.A. of Singapore, was fined $53,000.

All three companies complied with ARB's investigation and agreed to abide by all pertinent ARB regulations, follow fuel switchover requirements, and keep accurate records. The fines go to the California Air Pollution Control Fund to support air quality research.

The ARB conducts over 500 ship inspections each year, checking for proper fuel usage, record-keeping and other compliance requirements, and takes marine gas oil or marine diesel oil samples for submission to the ARB laboratory to ensure they meet California standards for sulfur.

Compliance rates with ARB's Ocean-going Vessel Regulation, adopted in 2008, is very high, hovering around 95 percent. The measure eliminates 15 tons of diesel particulate matter - a known carcinogen - daily from ocean-going vessels' exhaust. The regulation is considered a vital tool in helping to reduce cancer rates and premature deaths for those who live near the state's busy ports and trade corridors.

Diesel exhaust contains a variety of harmful gases and over 40 other known cancer-causing compounds. In 1998, California identified diesel particulate matter as a toxic air contaminant based on its potential to cause cancer, premature death and other health problems.