When Bill Baker of Redding, Calif., questioned in 1995 whether a bottle of Heinz ketchup he bought was short of the listed weight, he set off a statewide investigation and consumer protection lawsuit lasting five years. Heinz agreed Wednesday to overfill plastic containers for the next 12 months to settle the complaint, and said it has been doing so ever since the short-weight problem arose in 1995. Spokesman Michael Mullen at Heinz headquarters in Pittsburgh said the short-weight was due to loss of moisture in new “more environmentally friendly” plastic containers Heinz began using that year. He said the problem was corrected within weeks and was confined to products sold in California. With Heinz required to put an additional 1% ketchup into each container for another year, the stipulated agreement filed in Shasta County Superior Court Wednesday will require about 10 million extra ounces in Heinz 18- to 64-ounce ketchup containers sold in California, at an estimated cost to the company of $650,000. Heinz also agreed to pay $180,000 in civil penalties and costs.