Here is statement from Seaward Electronics about the Type C:
The Seaward Type C was certified by the Factories Inspectorate in the U.K. as Intrinsically Safe, as defined in BS 1259:1958.
B.S.1259 was superceded by B.S.5501-9:1982 and more recently by both BS EN 50014:1998 and BS EN 50020:2002. In addition, the ATEX 94 Directive now applies in certain countries to equipment used in explosive atmospheres and places a different interpretation on the term ¨Intrinsically Safe". The Type C has not been certified as compliant with the ATEX 94 directive.
In an environment where ATEX 94 applies, the purchase of the new Type C to carry out essential electrical safety tests should be subject to a risk analysis by the site safety officer. For environments where the ATEX Directive does not apply, the original certification and "Intrinsically safe" marking remains valid.
* Prices excludes delivery carriage @ £10
and VAT @ 17.5%
Conforms to UK Electricity Council Engineering Recommendations G9