The Chemical Activity Barometer (CAB) of the American Chemistry Council (ACC) was up 0.1% in April, as measured on a three-month moving average, the US chemical producers' association said.

Having reached an index of 98.1, last seen in January 2008, ACC said the CAB - reflecting production, equity prices and product prices, along with other indicators - remains 2.6% ahead of the year-ago figure. This, it says, suggests that gains in business activity will continue into the fourth quarter.

"All of the major production-related indicators are up and we might continue to see a strengthening. Construction-related chemistries have been adversely affected by bad weather so far this year, but we expect an improvement as we get further into spring," said Kevin Swift, the association's chief economist.

"The data on plastic resins and polymers for packaging suggest that retail sales should continue to be strong as well," Swift added.

The activity barometer is derived from a composite index of chemical industry activity and, as the industry has been found to consistently lead the US economy's business cycle, it can be used to determine turning points and likely trends in the wider economy.